Article 24. In order to exercise the privileges of a licence the holder must have a valid certificate of revalidation. Cs of T don't exist for JAA ratings.
To get the C of R within the validity period the holder must complete 12 hours in the 12 months preceeding expiry, including a Dual training flight with an instructor. This can be any instructional flight of at least 1 hour.
I presume this is what you mean by a check out.
As the licence holder must have at least 6 hours PIC and 12 take offs and landings, there is no mandatory requirement for the Dual Instruction. If you require guidance there is an AIC 127/1999.
Alternatively, the C of R can be revalidated by passing a proficiency check with an examiner in accordance with App 1 & 3 to JAR-FCL 1.240.