How to temporarily override System Variable faBackendUrl

Summary:

Content (required):

This is how instances are currently set up:

• dev1 - development instance
• test - UAT instance

We are developing an Application Extension (App UI) to extend accounts SUI and we are at the point that we are connecting the VB Studio UI that we built with Oracle Fusion Cloud Application. However, the changes we have in the metadata are in Dev1 and we need to be testing our connection with Dev1. But the dynamic setup of the service connection keeps pointing us to the test instance and upon checking we discovered the system variable faBackendUrl. Is there a way for us to temporarily override this system variable so when we try to run/test the application