Welcome to the Board!
What do you mean by "replicated"? "Replicated" implies a complete copy. If that is the case, then it should be no problem to modify, as their is no connection to the original.
If you really mean "split", where the back-end is located elsewhere and linked to the front-end, you will need access to the back-end to modify it. It should be easy enough to find where that is located. Just right-click on a table name and selected "Linked Table Manager". This will list the path where the back-end tables are located.