I believe what you want is reversing an animation, not mirroring it. But just so you know, the animation is not just the reverse of the other. If you watch someone duck, and then get back up, they shift their weight into different places, and the anticipation is quite different. Just reversing it will most likely look quite strange.

One way to reverse an animation is to do the following: https://simplymaya.com/forum/showpost...98&postcount=3