Guild Wars 2

Ok thanks, I think I know the problem, I am trying to put a 39 rune into a 35 piece of gear.

New to the game, and I put the wrong rune into a piece of armor, it wont let me change the rune out, are you able to replace runes multiple times? Or can you only change it once, when you get it?

I just bought this game a few hours ago, I hope this isn’t the norm.