S.T.
if you approach the principal reasonably and make logical arguments for your daughter to remain in her school, and it makes sense for her to do so, that should be all you need.
there is no magic incantation, at least that i know of, and i'm in the bidness.
how far out of the district are you? do you have daycare that's still in the old district? how do you plan to get her to and from school? is there something particular about the old school (or something wrong with the new one, for that matter) that would cause your daughter undue trauma if she had to move?
because switching schools, while certainly disruptive and sometimes upsetting, isn't actually an issue in and of itself. kids move and switch schools all the time, and unless you have a compelling reason that your daughter is either too fragile to withstand it, or being so brilliantly supported at her old school that it would be measurably beneficial for her to stay, this is probably not high on their list of priorities.
if it's just the old 'my child is special' that principals and teachers hear every day, you probably won't get too far.
khairete
S.