Revert merge postman from fork to master

I am using postman and I have 2 workspace master and personal workspace. I am forking the collection in the master into the workspace in the personal workspace. Then accidentally there is a wrong merge from fork to master. how do I revert the merge in postman? is there any way because i am searching in https://learning.postman.com/docs/collaborating-in-postman i couldn't find anything about revert the merge