I lost auto pressurization one day in a B737, switched to standby and that didn't work so went to manual and was able to maintain pressurization. We also previously had lost the autopilot so were hand flying so when they told us to hold going into SFO from SEA told them we kind of had our hands full and holding was not a good idea so they gave us a break and let us continue our descent for landing. No need for an emergency descent in our case but we were busier than a one armed paper hangar.