this is actually a very easy problem to fix just takes a lot of patience.
first you start off on the ground, you put pressure on her left side with the heel of ur hand and ask her to move away, make sure ur hand is in the same exact place u would have ur leg, if ur asking her to bend then when put pressure with ur turn her head with ur hand on the lead rope.repeat this for a while until she gets it.
once she understands that then u can move to doing this in the saddle, always start at a walk and work on it for a week, then u move to a trot the next week if she is getting it and then a canter the next week, but only if she/he is getting it.
for instance if ur trying to get her to bend around ur left leg, put slight pressure with ur left leg on the girth and pull ur left hand back showing her u want her to bend, same on the other side.
if ur trying to get her to move off ur leg slide ur left leg back off the girth and keep pushing until she moves over a step, remember everytime she does it right even if its just bending a little or stepping over one step praise her so that she understands she did it right.
but like i said practice and patience is the key. if she gets confused when you start moving from walk to trot or trot to canter, go back to where she was comfortable and continue.
"The horse you get off is not the same as the horse you got on; it is your job as a rider to ensure that as often as possible the change is for the better."