If you've reserved/placed a hold on a TCC Library (non-ILL) item, you can log in to your library account and go to the "Requests" tab. See this FAQ for more details on how to access your library account if unsure. There, you can see the "Edit request" link:
Selecting the link will cause a popup to appear, where you can change your pick up location:
If it is an interlibrary loan (ILL), please see the below FAQ link on how to update your pickup location.