the tickets only start the first time you enter a park
so if you change your dates, the tickets will follow
the main issue is that the free dining ends tonight
you mentionned on the other thread you'd be staying at a all stars. The is only 1 CS credit per night for the free dining deal) and tomorrow this will probably end. QSDP and
DDP will most probably continue for moderates and deluxes (without a gift card) but Values will probably be out of this extended offer.
The other thing you need to consider is that there is only a limited number of rooms released for free dining.
When (and if ) you need to change dates, there will need to be a room, eligible for free dining, for your new dates. (even if the deal has ended the disney system remembers which rooms were eligible for the deal)
when you call to change your dates, if there is no room eligible for the FD deal you locked in, then you won't be able to change your dates and keep your free dining.