Originally Posted by jsloan

OK. If this was a fare to EWR — that is, EWR was your original destination, and now it’s the origin of your return flight and not a connecting point — you can approximate your refund easily. On your original receipt, find the estimated accruals. Whatever the ratio is there, apply that to the total fare and you’ll be close. If the accruals were 50 PQP for the outbound, 50 for the return, and a $120 ticket, you’d expect $60 back. If they were 50 PQP outbound, 100 for the return, and a $180 ticket, you’d expect about $120, as two-thirds of the accrual was on the return leg.

If it was a fare beyond EWR — example, you were flying TPA-EWR-MAD and are now returning along the same route — it gets considerably more complicated. You can estimate it using the same approach, but it’s a much, much rougher estimation.