Rig Pivoting Problem

Whilst animating the struck animation I've come across a problem that I am struggling to solve. The pivot of the staff/hand needs to be changed mid animation, but doing so causes the start of the animation to use the latest pivot placement throughout the entirety of the animation. When the character gets struck I need the pivot to be placed on the bottom of the staff to allow it to rotate forward as to produce a clean and believable representation of an overlapping action. I can do this by moving the pivot to the bottom and it works well. I then need the pivot to be placed back at the wrist position so I can thenceforth move the staff and hand with it pivoting around the wrist. That is easily done, but now when I play back the animation the rotation and translation information uses the pivot where it was last placed (the wrist), and therefore the clean believable overlapping action of the staff no longer takes its pivoting information from the bottom of the staff, but from the wrist, making it translate out of place.

A few images to illustrate the problem:

Pivot placed at bottom of staff for clean rotation forward.

Clean rotation forward.

Pivot moved to wrist for the next set of key frames.

The start of the animation now takes its pivoting information from the latest pivot placement, the wrist.

Compare this image to the image above and you can see the staff has moved its base, and is now following the wrist pivot instead of the initial pivot at the bottom of the staff, causing it to change its position at the bottom of the staff and therefore becomes an unrealistic movement.