I work for a small engineering consultancy (as an engineer) and have recently taken on the role of being the point of contact for applicants. I recently offered a summer internship to a student with an impressive CV and appropriate skills. The student unfortunately received an offer from a firm in their home town so took their offer over ours to be closer to family. I noticed all the advice on here and other sites I frequent over advice to the applicant but not to the interviewer.
What is the best way to tell the candidate "thanks for being part of the application process, congratulations on your other job, the door is still open in the future, all the best in your career"? In a professional manner.