Not according to the Pass Travel Policy Page on Deltanet:

Pass Allotments

S2 Priority flight day allotments are renewed on each employee's pass eligibility date. Flight days may only be used during the pass eligibility year to which they are allotted. The allotment may not be carried over from one pass eligibility year to the next.

S2 Priority standby code travel is permitted on an unaccompanied basis. Remaining flight days (except flight days used within the past two calendar days) may be checked on TravelNet.