The single biggest reason Amazon sellers stay with a bad prep center is the fear of switching. Every switch carries real risk of a stockout, a BSR collapse, or inventory getting stuck in the old provider’s warehouse while they take 30 to 90 days to release it.
None of those have to happen. The switches we have run at KL Productions take three to five business days end-to-end, with no BSR drop, no missed FC appointments, and no inventory held hostage. This is the day-by-day playbook. It scales from a 500-unit-per-month seller to a mid-five-figure account.
Before day one: the prerequisites
You cannot run a clean migration without three pieces in place. If any of these are missing, fix them first.
1. You have a working FBA inbound plan for the next 30 days. If you are about to stockout on your hero SKU next week, now is the wrong time to switch. Switch AFTER the next inbound cycle, not during.
2. You have your current inventory position documented. Pull your Seller Central inventory report. Note: what is at FC (active), what is in-transit, what is at the old prep center’s dock, what is in long-term storage.
3. You have a signed MSA with the new prep center. Switching is 10x faster if the MSA is done, the COI is exchanged, and the new prep center already has your WMS account provisioned. Do not start the switch conversation with your old provider until the new side is ready.
At KL Productions, step 3 typically takes us two to five business days from first call to signed MSA. We will send the MSA, SLA preview, and COI inside one business day of your quote acceptance.
Day 0: The departure email to your old provider
Most sellers agonize over the departure email. Do not. Short, direct, and paper-trailed is the right move.
Template:
Hi [Account Manager],
We are moving our prep operations effective [date two business days out]. Please consider this written notice of termination per the MSA.
Three asks:
- Please confirm receipt of this notice and your expected timeline to release my remaining inventory
- Please pause any inbound from my suppliers and ASN’d freight. My new prep partner will provide updated routing
- Please send me a current inventory count by SKU and location within your facility by end of business tomorrow
I appreciate everything and wish you well. Thanks for the collaboration.
Best, [Name]
Send this in writing (email), not on a phone call. You want the paper trail. Do not explain why you are leaving. Do not leave room for “let me talk to my manager about discounts.” You have already decided.
If your current MSA has an exit notice period (30 days is typical), reference it. You still send the notice now so the clock starts.
Days 1-2: Inventory coordination
The old provider owes you a SKU-by-SKU inventory count. Usually they deliver this within 24 hours because they want the relationship ended cleanly too.
Once you have the count, the new prep center needs three things from you to plan the receiving:
- SKU list with case pack quantities (how many units per carton)
- Expected inbound freight type (LTL, full pallet, or small parcel) and approximate arrival date
- Pack-out spec for each SKU (FNSKU? polybag? bundling? hazmat?)
At KL Productions we can take this data in a Google Sheet. We do not require you to fill out an intake form with 40 fields. Email is fine.
The goal in days 1-2 is to have the new prep center ready to receive the exact inventory that is coming, with pack-out specs pre-configured in our WMS. This eliminates the dock-receiving delay that normally eats three to five days when a prep center is figuring out a new client’s SKUs on the fly.
Days 2-3: The two-shipment window
The key to a clean switch is running two parallel shipments. While the old provider is shipping out the last of your prepped inventory to FCs, the new provider is receiving and prepping the next batch.
Phase A: Old provider ships out your existing pre-prepped inventory. This shipment is already paid for and already on their dock. They should get it out the door within 48 hours of your departure notice. If they stall, ask for a specific ship date in writing.
Phase B: New provider receives your next inbound freight. This is the shipment that was scheduled to go to your old provider. You redirect it with an updated BOL (bill of lading) or ASN (advance shipment notification). If the freight is mid-transit, the carrier can re-route to the new destination for a small fee.
Run both shipments at once. Your FC never has a gap.
Day 3: The physical inventory transfer
If you have inventory physically sitting at the old provider’s dock that has not been prepped and shipped yet, you have two options for getting it to the new prep center.
Option A: Let the old provider ship it to Amazon FCs as originally planned. Cleanest option. They prep and ship the last batch, send you the final invoice, and the relationship closes. Works if their prep quality is acceptable for the remaining inventory.
Option B: Physically move the inventory from old provider to new provider. More complex but sometimes necessary (for example, if the old provider’s prep quality is why you are leaving). You arrange an LTL pickup from old provider’s dock to new provider’s dock. Typical cost for a West Coast to West Coast move is $400 to $1,200 depending on pallet count.
At KL Productions we have managed option B migrations where the old provider stalled. The key is getting the written inventory count in days 1-2 so you can dispatch an LTL carrier without ambiguity.
Days 4-5: First outbound from the new provider
By day four or five, the new prep center has received the inbound shipment, prepped it to spec, and is ready to ship to FC. Your first KL Productions outbound goes out on standard Amazon Partnered Carrier or your preferred LTL partner.
The first shipment is a small stress test. Watch for:
- Did the inbound get received within the SLA window?
- Were FNSKU labels applied correctly? (Pull a random sample and scan)
- Were hazmat SKUs handled appropriately?
- Was the invoice on rate card with no surprise line items?
If any of those come back wrong, flag it immediately. A good prep center fixes it before shipment number two.
At KL we run a first-outbound QC review on every new client’s first shipment. Trevor or the ops lead walks the pack line with the client on Zoom if they cannot be on-site.
Days 5-10: Settle-in period
The next five business days are about rhythm, not disruption. Your new prep partner is processing inbound shipments on standard cadence, outbound to FC is running, and your inventory position at Amazon is stable or growing.
Watch the BSR on your hero SKUs. A clean migration has zero BSR drop. If you see a drop, trace it back: was there a gap in FC receipt, or was the drop unrelated to the switch?
Start the monthly cadence:
- Day 7: First weekly check-in with your named account manager
- Day 14: Monthly accuracy scorecard baseline established
- Day 21: First month’s invoice arrives — review line by line against the rate card
Day 10-14: Close out the old provider
By day 10 your old provider has shipped out your last remaining inventory (or you have moved it physically). They will send a final invoice. Pay it. Request confirmation that your account is closed and all inventory is released.
At this point you have:
- Switched prep centers in 10 to 14 business days end to end
- Zero BSR drop
- Zero missed FC appointments
- A paper trail of the transition for your records
- A new rate card you can share with your CPA and your bookkeeper
The things that go wrong
In the 12-plus migrations we have run at KL, three things have tried to derail a switch.
1. Old provider holds inventory past the exit notice. Rare but real. The fix is a written notice referencing the MSA’s exit clause, followed by a letter from your attorney if needed. UCC §7-209 governs warehouse liens; if they are asserting a lien, they must do so in writing with specific charges owed. Most providers fold when the paper trail starts.
2. New prep center fails the first outbound. Rare when the MSA is done right. The fix is to have the SLA written in advance with a specific remedy for first-outbound errors. At KL, FNSKU mislabel on the first shipment is a full refund plus Amazon removal fee reimbursement, same as on any shipment.
3. Inbound freight gets stuck between providers. Your inbound freight was going to the old address. You redirected it. The carrier lost the new address. Fix: ALWAYS work with the carrier directly to update the BOL, not through the old prep center.
The switching checklist
Copy this and work through it in order:
- Signed MSA with new prep center
- COI exchange and verification
- WMS account provisioned at new prep center
- Inventory position documented from Seller Central
- Departure email sent to old provider
- Old provider’s inventory count received and reviewed
- SKU list, case packs, and pack-out specs sent to new prep center
- Inbound freight rerouted to new address
- Old provider confirms last-outbound ship date
- First new-provider inbound received within SLA
- First new-provider outbound to FC completed
- Old provider releases remaining inventory (or it ships out)
- Final old-provider invoice paid
- Account closed confirmation from old provider
If you want the SOW template or the migration-plan Google Sheet we use with new KL clients, contact us and we will send it inside one business day. No email gate.
Trevor writes the Field Guide himself from the KL Productions floor. No ghostwriter, no definitional 101 content, no AI-smoothed marketing posts. If he did not work through it on the floor, it does not go out under his byline.