Can I reverse a "Synchronize" operation?

Newby, here. Apologies if this has been covered.
I tried to set synchronization for a subfolder and actually synchronized the parent folder by mistake. I do not see any way to "unSynchronize" the parent folder and it may be a problem soon. Any help for me?

It occurred to me that this operation is merely a one-time function and that I might just delete the contents of the parent directory from the storage drive, but I fear making the problem worse if I do not confirm that with an experienced user. If I'm wrong, then the program will continue to replace the files I do not want synchronized.

There is not way WinSCP would reverse the operation for you.
You have to do it manually.
And it's one time operation. WinSCP will not synchronize again on its own.

I am deleting the segments that were not intended for Synch. Documentation for the synch function seems rather sparse.