5.6.3  An Athlete who is not in the IBU RTP who has given notice of retirement to the IBU/BIU may not resume competing unless they notify the IBU/BIU and their National Anti-Doping Organisation at least six months before they wish to return to Competition and make themselves available for unannounced Out-of-Competition Testing, including (if requested) complying with the whereabouts requirements of Annex I to the International Standard for Testing and Investigations, during the period before actual re-turn to Competition.