How to transfer an Invoice that is paid under one customer to another customer and mark it as paid on quickbooks desktop?

Hello there, boxesrus.

The best way for us to correct the transaction from Michigan Caterpillar to Caterpillar is to delete and recreate it.

Since there's a payment associated with the invoice, we'll have to delete both the invoice and payment. We can do it from the customer's account. I'll show you how:

1. Go to Customers. Then, Customer Center. If you mean this transaction is for the vendor, go to Vendor and select Vendor Center.
2. Find Michigan Caterpillar.
3. Click Transactions. Set the date when the transaction is created.
4. Locate and open the payment first, then delete it.
5. After that, locate and open the invoice, then delete it.

Once done, recreate the invoice for Caterpillar and make a payment with it. Then, you can do a mini reconciliation method to correct your reconciled account. For more details, we can refer to this article: Reconcile previously deleted and re-entered transactions. This provides complete steps and instructions. 

Also, we can check these articles for additional information about the reconciliation process in the program:

• Reconcile an account in QuickBooks Desktop.
• Learn the reconcile workflow in QuickBooks

Let me know if you need help with handling transactions and more details with reconciliation. I'm always glad to help in any way I can.