CO2 absorption question

I’m fairly sure I know the answer… but if I blast a keg with 20 psi and then unhook the gas will the beer absorb the co2…or does it need to be under constant pressure?

I do that so much… It works! I will do that a couple of times as I am carbing up a keg… I even do that when I have to put a keg in the other regular fridge… Yes when you pull a pint, do add CO2… Sneezles61