Unable to combine 2 animations

I made an animation. I made a seccond animation that was suposed to go right after the first. I made a scene 2 and when I copy the frames over it says:

Resolve liprary conflict, One or more library items already exist in the document. Replace existing items or dont replace.

If I replace the one works right but the first doesnt. If I dont replace the first one works but everythings all messed up in the other one.

Is there a way to combine the 2 animations together?