By default, your booking o board is automatically transferred to the TA who booked your current Celebrity cruise that you are sailing on. However, you can always request to NOT transfer it to the TA (albeit signing a paper just like someone has mentioned above). Then the booking will belong to Celebrity. When you get home, you can still contact another TA that you like, and have this booking be transferred to them. As long as they do not change the booking number (which they don't), you will still get all of the OBC and whatever goodies promised when you made that booking, plus probably additional goodies from this new TA.