Originally Posted by tennisguru

If coverage is black then a PD will not work. You can IVD or APD a day as long as you have at least 25% of the required reserves available.

The last chance to make an X day swap is the 2200 run on the 4th day prior. So tonight (Tuesday) at 2200 is your last chance to make a swap that affects Friday. You can no longer make a swap that afffects Thursday. Assuming that you are not dealing with a holiday blackout period, you need to find a way to swap into worse coverage when the day you want to swap out of is black. So if that day is 22/25 (-3), then you'd need to find an X day that is adjacent to a LC day that is -4 or worse and the swap will go through assuming you are not reducing your original LC block to less than 3 days in a row on a NB.

You can APD/PD/IVD a reserve day as late as the 0700 PCS run the day prior, HOWEVER, that only works if you do not have an assignment that touches that day. Once you've been assigned a rotation or SC you can no longer drop any of the underlying reserve days.