You can make elements in your banner ads uneditable by locking objects, so they stay the same.
Log into your BannerBoo dashboard, click on the banner, and it will open in edit mode. \
Now click the object on the stage that you want to lock and click on the Lock icon in the work area — the layer will be locked.
Check the animation below and follow the process as explained.
Make sure that the layers you don't wish to edit are locked when you update the creative to ensure that nothing is changed accidentally.