Tracked changes
If you are doing a revision in Studio, check if the project instructions ask you to use tracked changes. If they do, toggle on the Track Changes function in Studio under the Review ribbon before you make any changes in the files.
If you want to view the revised translation without the tracked changes, use the Final Mode button to toggle the changes on and off momentarily.
If you are finalising a file that has been revised using tracked changes, make sure to either accept or reject all changes in the files, and make sure all segments are confirmed before you deliver any finalised files.