Hello! I found a good source that may be helpful to you: http://practicalhorsemanmag.com/training/flying_lead_changes_051810 Hope this helps! 🐴😊

My horse is very young so this may not help but with him I'll canter full arena on the correct lead, then cut across the arena and switch directions, while doing a small half halt and really scooping into the saddle. Just a suggestion ;)