Once you become a Participant, you will remain a Participant so long as you either (i) have a vested Accrued Benefit that has not been fully distributed or (ii) have not incurred a Permanent Break-in-Service. Article 6 explains the vesting rules, and generally provides that your Accrued Benefit becomes vested once you earn five years of Credited Service before incurring a Permanent Break-in-Service.