I appended an object to my scene that already has the animation I want it to have, and I want to rotate it so that it's facing another direction. The problem is that after I rotate it when I go to test out the animation it snaps back into its original position. I was also hoping to scale it. Thanks in advance.
When you model snaps back it could be that you didn't keyframe the location of the root bone or simply single object. When you add keyframes in the default layout all the keyframes are added to a default action e.g. if the name of your object is cube the keyframes will be added to CubeAction.
You could create another Action to take only the additional rotation keyframes and add the current Action and the Rotation-Action to two Stripes in the NLA-Editor. You have several options on how the Actions are blended and where the blending starts.
A more detailed tutorial description