Base swapping really shouldn’t have anything to do with a vacancy. They way we did it at ASA was through the Union. If there were two pilots that flew the same aircraft but wanted to swap base they would contact the union. The union would post the trade for 30 days on the website an crew room TVs. If a senior pilot saw it and wanted to take the trade from the junior pilot they could, if not after 30 days the trade is finalized and we notified the company. They usually moved bases on the next monthly bid.

This process had nothing to do with vacancies. If the company wanted to reduce the base by not awarding secondaries they could still do that. It keeps the base and the exact same level the company wants it since it is a one for one trade.