By cancell you mean? When the flip starts do the run input?You just need to work on the timing of hitting ff block at the end of the flip kick animation so you are to the point where you trust that it is going to come out when you expect it to. Just work on cancelling her backflip into run over and over until you get the timing window down. Since most of the time she has to go into run is off the backflip you should be able to get pretty consistent on the timing without too many adjustments.