AFAIK, no skills test, revalidation or any form signed by an examiner is required as long as the rolling validity requirement is met ie
He has completed, in the last 24 months, as pilot of an aeroplane or TMG:
At least 12 hours flight time as PIC, including 12 take-offs and landings; and
Refresher training of at least 1 hour of total flight time with an instructor.
However, it is probably wise to have the instructor sign the training time in his log book.