Yeah I'm new. How dies one go about taking a nock off the string? Say you have one on the string but want to just use a floss nock and you need to get brass mock off. Is it a simple case of prying it off?

Easiest is to cut the string with scissors right above the nock and then right below it.
You will need a new string, though.

Ok, for real... nock pliers have a little deal that opens the nock up so you can move it or take it off. If you don't have those see what you can use to pry it open but be very careful to not damage the string.
If you have a local archery shop they should have the tool and maybe won't charge you to take the nock off.

Guy

A nockset can be removed with an inexpensive set of Nockset Pliers. Other than that, just pry the brass nockset open and remove.

Joe

Find someone with a set of nock pliers all archery shops have and one of your shooting buddies must.If you try to pry off with normal plyers you will most likely wreck your string!!

Now I know, guess another order to 3rivers is coming up.

Just use a pair of needle nose pliers if you don't have nock pliers, be gentle and just try to grab the edge of the nock and pull gently. It's only brass and bends easily with a little force. If nothing else use a small screwdriver to pry one edge of the nock away from the string enough to get it off without damaging the serving.

Just be careful you don't damage the serving or you will be making a trip to the bow shop anyway.

flat tip screw driver (very small) and needle nose pliers work.

Butter knife.

When I still used brass nocks and had to remove them I always unstrung the bow so there was no tension on the string.  Don't know if it really mattered but it eased my mind.

Next I took two pair of needle nose pliers and pulled the nock open.

I learned how to tie on an adjustable  screw type nock and that's all i use anymore.  There is a how to article about this nock that might be of interest.