C.4.4  The Athlete shall retain control of the collection vessel and any Sample provided until the Sample (or partial Sample) is sealed, unless assistance is required by reason of an Athlete’ s impairment as provided for in Annex A -  Modifications for Athletes with Impairment s. Additional assistance may be provided in exceptional circumstances to any Athlete by the Athlete’s representative or Sample Collection Personnel  during the Sample Collection Session where authorized by the Athlete and agreed to by the DCO .