To change the title of your report, you will need to SAVE it to a Bundle.
To change the title of a report already within a Bundle, you can do this on the Bundle screen.
Find the Bundle > Report you wish to rename
On the right hand side, click on More Options > Edit Properties
Then you can overtype the NAME which is what shows in the Report Bundle
or the TITLE which is what shows when you run the Report
After you have made a change, click SAVE PROPERTIES
Run the Bundle to check your changes