CVS asks you to submit vacation requests in October/November for the following year. Depending on the district, they tend to block requests of 3-4 consecutive weeks. Even 2 weeks can be a problem sometimes. If you manage to get your 4 week block approved by your scheduler to be taken in January, and you quit soon after, you might have beaten the system. However, since it is common courtesy to give 2 week notice, at least to stay re-hirable in the system, they will probably deduct any un-earned vacation time from your last pay check.
So you will get a pay out for any vacation time you earned. As was mentioned before, it is pro-rated. I left in the summer but stayed in the system and was kicked out of the system 4(?) months later due to inactivity. I thought I was all done with. However it was nice to get a goodbye PTO/vacation payout check following February.