Dear Mrs. Owl,
I know you are a vice principal now, and I can't think of anyone better for that job. In some ways, I imagine that vice principal is a harder job than principal. It is a fine line to be able to support a principal and still be accountability and a voice of reason when necessary. I know you will be so good.
I know you less than everyone else I've thanked, but that is why the help you gave me meant so much. You had nothing to gain by helping me. You weren't afraid to tell the principal her evaluation of me was wrong. I know that was a risk for you.
Thank You! Thank You! Thank You! Thank You!