Go to the coach and tell her she should kick the girl off the team
Tell her that she can't miss anymore practices and give her a warning that she might get cut.
Do nothing and make an excuse for her when the coach asks where she is.
Talk to her and say this is her last chance and then she will get cut if she continues to skip practice.
Make the signs by yourself to make sure it gets done
Ignore it. If they didn't do it they can take the blame.
Gather up the squad and make a bunch of posters together.
Assign a couple of reliable people to do it. You have an exam the next day and education comes first.
Call the people you are close with and get them to pass it on.
Call everyone until you are positive everyone knows about it.
Call one person and get them to tell everyone.
Don't call anyone and hope that the coach does it just to make sure everyone knows.