Allows you admission for 6 days into Magic Kingdom, Epcot, Disney-MGM Studios, and Animal Kingdom. You can also hop between Disney Theme Parks on the same day. Your pass expires 14 days after your first day of use. 

You can certainly add the No Expiration Option onto your pass. If you would like to add the No Expiration Option to your ticket, your unused days never expire. Your unused days are good for a future visit to Disney World.