Beachbum.... I think I have a good idea of what is going on here.... Issues with either of two things would warrant schedule changes.
1. Bullying... If there is a bully who MUST be removed from another class or a bullied child who just must be removed from the class where the behavior is occuring (and this should happen if all other avenues have failed to protect the bullied child) This would be taken under serious consideration. And mid-year would be the best time to make this happen.
2. IEP requirements... If it has been determined that the school is not meeting the needs of students who have valid IEP special needs (remember, I am the parent of a son who has very significant deficits in math skills) Then if they are required, by Federal IEP law/guidelines to, for example, provide another IEP inclusion classroom, with smaller class size and a SPED assistant... Then this also might be something that would just have to happen.
Either of these things are just so bad for a student like yours, who is kind of having to accept the shorter end of the stick. And, that is just awful.
Could other kids have been moved???? Yes... But, if the teacher openly admits to chosing to move your daughter and her friend, together (which is probably a nice gesture, a good thing????)
We don't have enough info here to give good advice.
Just know that if you really, really, want to try to keep your daughter in that classroom, you must go in with a positive attitude. Many times school staff can be just rude and dismissive and not wanting to hear from 'one of those parents'. But, there is also the chance that if you go to the right person in guidance/administration, with the right attitude... somebody might be able to help you.
It will work out, either way!!!
Good Luck!