Also stay in the loop with what's going on through these awesome links:
Now once invoice is created and partially paid you cannot change the figures billed to client. The problem is that, if for example, a client reduces the work to be done after making partial payment, the invoice was for the initial cannot be change. For example sent invoice to client for $13900, client paid $10,000k and decided to reduce amount of work to amount already paid. Now you cannot edit invoice to change the initial amount from $13,900 to $10k.
Please show me a screenshot, maybe I will better understand this problem and be able to advise something. You can use https://www.movavi.com/learning-portal/snipping-tool-for-mac.html to create a high-quality screenshot
Attachments Open full size
You say this is something that already exists, but it's June 2021, and it's still an issue.
Attachments Open full size
You can not edit once a partial payment is made. That is the issue the original post wanted to address and we are having the same issue.
Attachments Open full size
You have the ability to edit invoices until they are paid.
Attachments Open full size