If two users edit a page and their changes threaten to overwrite each other, Telligent Community gives you a way to view the other user's changes or overwrite them.
View the other user's changes
If, upon attempting to save, you receive a message on your wiki page stating that "User x posted a new version while you were editing," you have the option at the bottom of the page to overwrite the changes by clicking Overwrite or to View changes. View changes will open a window showing what was deleted or added in their version. If you want to let their changes remain, you can elect not to overwrite.
Overwrite another user's changes
Choosing the overwrite option will make your revision the current published version and will make the other user's version a previously saved revision (which you can revert to if necessary).