How do I set up to edit but not save the file

Document Server version:7.4.1.36
Document Server docker
OS:centos 7.9
Browser version: edge
Which parameters control whether the changes are saved?
I hope that some files can not save the modified content, keep the original version, the modified content can be downloaded. What parameters should I set so that I can edit the file but not save the modified file?

Hello @lfvan
Please clarify your request, its final goal is unclear. Are you checking Document server integration with your own self-written app? What is usage scenario for your goal?