Here's the problem, Dallas knows she's the one in charge.
When she cantered with the other horses, she made that decision, not you. Then when you turned around and asked her to canter, she did what a horse does in a herd when another horse pushed them to move and they don't feel the other horse has that right, she kicked out.
The best advice I can give you is to get on the ground and start doing some groundwork with her. There are some good threads here with advice about groundwork, and some great videos online, but nothing beats actually getting out and doing it.
You'll need either a roundpen, or a small paddock, a lead line that is long, GLOVES (seriously, rope burns = not fun) preferably a rope halter, and a flag that gets her to move, like shredded plastic bags tied to the end of a dressage whip.
Your goal in the groundwork is to decide how and when the horse moves and not allow any movement that you did not sanction.
You should get the horse going around you in a trot. If she tries to stop, you have to get her moving, if she tries to change direction, you make her change it back until she is going the way YOU decide, and you keep her moving until she starts to show you signs that she's thinking "Okay, you're the boss!" She should flick her ear toward you, then lower her head, then start chewing.
Once she gives you good signs that she is indeed admitting you're the boss, you let her stop and rest. If she is indeed starting to see you as the leader, she should turn to face you when she does stop.
Groundwork can be tricky. It does take some guts, and practice. Be sure to mind your space and keep the horse out of it. Don't be afraid to be big and in charge, even if you have to fake it and inside you're screaming.
A couple of tips, if you drop a line, go ahead and let it go. Let the horse step on it if she's still being a brat, just keep her moving. Once she's showing you respect, then you can go back and retrieve it. Stepping on a lead line isn't going to kill her.
Also, remember to point in the direction you want your horse to go, and then use the flag and your body position to "push" the horse forward from behind the horse's shoulder. If you get too far forward, she'll stop and change direction, (which is how you force her to change direction) if you get too far behind, then the horse "runs away with you" and you lose control.
Remember that in horse hierarchy, he who moves her feet loses, so make her move her feet, not the other way around.
Google "groundwork" on youtube and you should find some examples of what to do.
That should help. The next time you get in the saddle, she should listen to you, not carry you around however she wants. But that also means being more assertive in the saddle and not allowing her to make decisions. If you didn't tell her to do it, she has to stop.
I'd also look into how to train, and use the one-rein stop, just in case you need it.