Section 5.10 - Declarations(1) The declaration of a greyhound out of an engagement is irrevocable.(2) Declaration in sweepstakes shall be made in the same manner as is provided for making entries therein to the Racing Secretary who shall record the day and hour of receipt and give early publicity thereto.(3) Declarations in purse races must be made by the owner, trainer or authorized agent to the Racing Secretary or his assistant at least ½ hour before the time designated for the drawing of post positions on the day previous to the day on which the greyhound is to race, or at such time as the Racing Secretary may appoint.