How can i change the skeleton of an animation?

Hello.
i am working on a TPS game, and at the moment i am using the default character.
I am doing the system to pickup guns, but i want to have the animations to aim and idle rifle, so i’ve downloaded the Animation Starter Pack.
So i started creating a blend space for my character and i could not found the animations of the starter pack, i checked it and i guess is cause they are set to diferent skeletons.
Can i change an animation skeleton?

You need to Retarget the animation to the new Skeleton

Broken link. Now it’s this one, I think.