The pistol has a tool to dump the air pressure. You could do it just by shooting it repeatedly, but the dump tool is QUICK! And loud. Use some ear pro.
I changed the fill valve on the pistol. Benjamin sent me a new valve under warranty and I replaced it without issue. Just had to know how to use teflon tape. :)
The stuff you don't know you don't know is the most dangerous. But you can learn...
PN