RTI P3 bottle removal

I just received a new RTI P3 and I know the bottle can be removed without taking all the air out of it. Is there any trick to doing this? Do I have to do anything else first? I have the power plenums in I want to install them but I'm a little nervous about taking the bottle off. Last time I did it with my FX impact I had to send it back because the air just kept coming out. Thanks in advance