Swapping finds pairings already awarded to more senior block holders that would fit on the block being built, and tries to replace the pairings of the more senior block holder with equally desirable pairings from either open time or other blocks.

pairings can only be removed from another block if an equally desirable substitution (that matches the bid that originally  awarded the pairing) can be made

        if a pairing is swapped from a block that is over the Threshold Credit Value, the swap must keep the credit value above the Threshold Value

        if a pairing is swapped from a block that is between the Minimum and Threshold Values, the swap must keep the credit value above the Minimum Credit Value

The  pairings need to match the exact same bid preferences (including honoring  any  Prefer Off or Avoid Pairings bid  preferences), but they don’t need to be the same as or equivalent to each other in aspects that the preference did not stipulate.

Swapping Example

Bidder A wants 3-day pairings with late pairing check-in  times and early pairing check-out times.

Bidder A is awarded a 3-day pairing with a late check-in  time and early check-out time, with a layover in LAS.

Bidder B wants 3-day pairings with layovers in LAS.

The N-PBS Scheduler can’t find a pairing in open time to  match this bid, but finds the pairing on Bidder A’s block. The N-PBS Scheduler  also finds a 3-day pairing in open time with a late check-in time and  early check-out time.

The N-PBS Scheduler moves the pairing on Bidder A’s block  to Bidder B’s block and the pairing from open  time to Bidder A’s block.

Bidder A is awarded a pairing that matches the bid preference  for 3-day pairings with late pairing check-in times and early pairing  check-out times. Bidder B is awarded a pairing that matches the bid preference  for 3-day pairings with layovers in LAS.