How to switch animation sets?

So here is my situation. I am making an fps game. I was wondering if there was anyway to switch between animations depending on the situation. Here is an example if you don’t understand. So at the start of the game, the player is going to have a gun, but further through the game, the player is going to lose it. What I want to know is if there is anyway to switch what animations the character uses to run, jump, walk etc. after the gun is lost?