Is there an access control over an document is being edited?

Is there an access control over an document is being edited?

Hello!

I would like to know if there is any access control like the concept of "checking out/in" of a document when a user is editting a file in the file folder using ZoHo document tool such as word.

An scenario would occurs that a user A is currently editing a document using Zoho Word while user B is downloading the file.

I would assume that there is no way for User B to know that the file is being edited by user A.

A further seceario would be that B download the file and edit on his/her computer and upload the file where I would assume the system would recognize it as a later version. The question is, what would happen if user A now save the changes. So what would happen?

Thank you very much! and sorry for the above wordy scenario description

David