(Note: I tried this in ver. 9.2)

Pre-req: A test should be open which contains instances that need to be updated.

Step 1. Automation -> Update Run Mode
Step 2. Automation -> Run

When you do #2, the "update run" dialog box will appear. There will be 3 instances, out of which only two will be checked (update checkpoint properties and update active screen images and values). You can check the first one (update test object descriptions) if you wish to update your test objects if changes have been made to them and have not been updated in the OR. When the test is run, objects in the test will be updated.