How do you fix a four beat canter

Well for all those horse people out there, that really know what they're doing, and know about footfallsl, how do you fix a faulty canter. I have a horse who used to show in the ring, before I owned him, so i know he knows how to canter correctly, its just getting him to do it right. It seems to me he is four beating his canter, instead of doing a proper 3 beat. Does anyone know how to fix this, and what i can do to correct.

Thanks for all the help!

My show mare will four beat canter if I allow her, and my trainer has been working me very hard to get her out of the habit! So I have a few definite ideas for you! My trainer says its common, especially in horses that have been trained to go slow without paying attention to the quality of their movement.

First, spend a fair amount of time lunging your horse at all 3 gaits and watch him move carefully. Make sure you can identify what a good canter looks like for him, and then when you think he 4 beats. (And yes, horses can four beat when cantering slow, it's actually very common!) I've been told to never allow my horse to 4 beat when lunging, so when I see it I'm to speed her up and to get her moving forward, even if it ends up a brisk canter. if she's 3 beating properly I just leave her alone, if she starts 4 beating I pick up the speed again.

Next my trainer has me do tons of excercises that don't sound like that have anything to do with a good canter, but actually do! I have to do alot of pivots on the forehand and the hindquarter and alot of haunches in work, all which seperates each part of your horse so you can direct them to be straight and true. Most of this work is at a trot and walk.