“Many thanks for your expert help over this past year.  It made all the difference to work with you, Sarah—your help from the ads to the placement of those ads to helping with questions for first interviews—this search turned out well because of your professional advice. I don’t want to say “can’t wait to work with you again” for that would mean an opening, but I now know that I have an HR professional I can turn to who will make all the difference.”