Deadline for enrolling your family/spouse/dependents or for opting out of the GSA Health and Dental Plans for fall 2017 is October 4th. You nee proof of coverage from an alternate plan to opt out of the health plan. No proof of coverage needed for the dental plan. Enrolling or Opting-out is for the whole plan year, ending August 2018. After the deadline expires, you will no longer be able to opt-out of the plans.