S.B.
I think what you mght have to do is switch to a weekly reward system.
I have several friends who do this.
For instance, don't take a toy or video game away just for a day.
That's not working. If your daughter loses one of those things, she loses it for the rest of the school week.
Talk to the teacher and have her send home a weekly report. If she gets a good report on Friday, she gets her toys or her video games back. If not, she can try better next week. That will certainly get it through to her that it's not just a whoopsie for a day thing. And, if she gets a good report, think of a reward that she will really like such as choosing a movie for the whole family to watch on the weekend or something like that.
As for sports, I was very strict with my kids about that. If they weren't keeping up in school with their assignments, etc......no sports. That might sound mean, but to me, school comes first. My kids didn't have to get straight A's or anything, but if they were goofing off in class or not using their time wisely, juggling school and sports was a privelege they had not earned.
I have a friend whose son did something really, really disrespectful to the teacher in class and he was given after school detention. His mother marched right in and pulled him out because she didn't think it was fair for detention to interfere with his karate class.
I, personally, don't think karate should have interfered with his detention and being disciplined for something he'd done that was very inappropriate. The whole thing completely undermined the teacher and the child didn't learn anything other than he didn't have to worry about getting in trouble at school because apparently karate was more important.
My kids were both bery involved in sports and they knew from the time they were very young, like your daughter, that the first thing they would lose would be a practice or game or tournament. It was something that really mattered to them and they didn't want taken away so it was good incentive to be on their toes at school. I had to take away a coulple of games from my daughter, but I never once had to do it with my son. He learned from her mistakes and knew I was serious.
I know your daughter is only 6, but the weekly report thing can be very effective and it's good to implement these things when they are young as opposed to trying to get them straightened out later after bad habits have formed.
That's just my opinion.
Your daughter may be acting up at school because whe likes the attention, because she thinks she's being funny, maybe she's bored.
These are certainly things to work on and get to the bottom of with the teacher. You might even need to let your daughter know you will be checking in with the teacher on a daily basis for a while so you can figure out what's best to do.
But try the Friday reward system. If she gets a good report, she can help make homemade pizza and pick a movie and you can celebrate a good week. If she doesn't get a good report, you still love her, talk about what she can do to do better next week.
I hope you get some good responses.