[LakeCleElum]

Breakers go bad over time. I've replaced many, even in a hot box. For your safety, switch off the MAIN. Then, pull the cover. You remove the breaker by putting your finger on the outside closest to the edge of the box. Pull outward, that end will come out, then grab the whole thing and pull straight out. You will see one wire is attached. Unscrew the clamp holding the wire and go to your hardware store to find the same type of breaker. Reverse to install.

Just avoid the temptation to put a 30 amp breaker in its place. A 20 amp break get by with 14 gauge wire - A 30 amp need 12 gauge.

I just added 2 new circuits last week going out to my detached garage. I added 2 breakers w/o shutting off the Main, but if it's your first time, don't do that.

(I'm not an electrician, but have wired 2 houses I've build w/o a single correction notice)

Good luck....