Right now at my regional I have the ability to let other pilots pick up my trips, and reduce my credit for that month as low as I want. I just have to pay health care out-of-pocket if I go below ~50 credit hours.

The ability to drop/post trips down to 0 hours credit (in theory at least...) is really valuable to me for some months when I would like extended/uninterrupted time off.

At the majors, does this similar ability exist across the board? Or does it vary by the airline, where some require you always maintain a given minimum credit (and if so, which ones allow)?