detailing different implementation of the same use case for different user types - Use Case Diagram

Question

I am making a use case diagram that includes multiple users. 2 of these users share the same use case but each with different usage.

In case a global use case diagram is already done and a detailed one I needed, how do I detail the difference in the usage of the use case shared by the two users ?

do I make a single diagram and put 2 users with 2 different use case trees from 2 same case ? or do I do 2 separate diagrams for each user ?

Edit : Example if 2 users can manage their account on a platform but one can edit all their profile's attributes and the other can't.

if I already made a use case diagram with both users sharing the same use case Manage account, how do I details this nuance in the actual usage with an other use case diagram meant to detail the Manage account use case.

Answer 1

The simplest solution is to rename the new use case so it has a different name from the existing one. Documentation (including diagrams) is meant to help maintainers of the software, not confuse them.

Once you've done that, you can create separate use case diagrams for each.