Hi Angelyn,

On the paid invoice that I have, there are no linked transactions (I went through your instruction below on how to check the linked transactions). In this case, changing the "Customer" to the project name (for it to be moved to Projects section) will not affect the paid invoice anymore like affecting the books, as long as I re-linked the payment into the paid invoice once I changed the invoice's customer to the "project"? 

My only concern is that if I will mess up the books once I changed the customer name to the project name because the invoice has already been paid. I hope you get my concern here.

Thank you.