I envision 2 ways:

Clicking "edit invoice" launches a modal that takes over the whole screen.

or

Clicking "edit invoice" allows the user to edit the details in line. If a user selects another row, a confirmation modal will take over the screen asking if the user wants to save or disregard changes.

I've written an article of dialog confirmation best practices: https://medium.com/nextux/designing-confirmation-278d159723e

What other ways are you thinking?