We are glad you are reaching out for help. This little gal has many years of classroom settings ahead of her, so learning how to handle her emotions now will serve her well in the future. When the younger kiddos have undesirable behaviors, it gives parents an opportunity to teach them a more socially acceptable behavior to use instead. So, when told she can't growl at people at school, she needs to be taught what she CAN DO! -- what she can do and say instead. Perhaps you have already done this but give her actual words she can say that express her feelings, and yet are more acceptable. It also helps to teach her something physical to do with her body, hands, feet etc., when she is angry and doesn't get her way. Teaching to a younger child should include not only telling what you want, but also showing her. Demonstrate the words and actions. Then to make sure she understands and can do it, have her demonstrate back to you.
As you know, having kids practice repeatedly is where the greatest retention takes place, so this should be practiced throughout the day when she is not in school. Use scenarios that are like those in school where she has struggled, and some can be pretend as well. Be sure to reinforce her for using her words and body language during practice. She will change if she gets more attention and recognition for doing the right thing, than she does for doing it in an unacceptable manner. The more she practices, the more likely she will automatically do it well back in the classroom environment.
Many children need preventive prompts so if you have access to school staff, let them know what she has been taught and has practiced. Encourage them to prompt her before a situation occurs that would have resulted in growling and misbehavior.
We hope this is helpful and remember to keep the teaching and practicing brief and fun and occurring frequently.
