Thanks for reaching out to us, @Sam071.

Yes, you’re right. Changing the customer name to match the project will remove the linked transaction. Since the invoice was converted from an estimate, the line items get cleared as well. 

You can delete the invoice and update the customer name on the estimate. From that, create the sales transaction and apply the customer’s partial payment to link them all under the same project. 

Here’s how to delete an invoice:

1. Go to the Sales menu and select Customers.
2. Click the customer’s name.
3. Under the Transaction List tab, look for the invoice and click the drop-down under the Action column, then choose Delete.
4. Hit Yes on the message prompt to delete the transaction.

Once done, open the estimate and change the customer name. Then, convert the transaction into an invoice. Follow the steps below:

1. In the Transaction List tab, double-click the estimate. 
2. Choose the Project on Customer drop-down.
3. Hit Save.
4. Click the Create invoice button next to the transaction amount.
5. On the pop-up, select the appropriate option and click Create Invoice.
6. From the invoice screen, click Save.

Right after, apply the partial payment (customer name should be the same with that on the invoice) by clicking the Receive payment button. Check out the following articles for more information:

• Delete an invoice or other transactions.
• Convert an estimate into an invoice.
• Record customer payment.

That should get you pointed in the right direction.

Leave a comment below and let me know how this goes. I’m always here to help. Have a good one!