You mean swapped places…
It's not common in my experience, but some chapels have only a center aisle. Probably older non-Catholic chapels that have been purchased by Trads.
So to preserve the pew seating arrangement the person closest to the center aisle exits the pew, allows the next person to line up in front of him, that person allows the next to line up in front, etc. etc. One entire side of the chapel goes before the other side so that there is half of the aisle open to return to the pews