“SkyWest expects the 16 new E175 aircraft will replace 16 SkyWest-owned or financed CRJ900s currently under its Delta contract, with expirations ranging from the second half of 2022 to early 2023. SkyWest is evaluating the impact of the anticipated displacement of the CRJ900s, including a potential non-cash impairment charge.”

It’s nothing more than a 1 for 1 to extend the contract via new contract with new aircrafts.