Changing IP Addresses of an Always On Availability Group in SQL Server 2014
Use the following steps to change IP address of the listener 

ALTER ENDPOINT [MyEndpoint]
      STATE = STARTED
      AS TCP (LISTENER_PORT = 5023, LISTENER_IP = (10.x.x.x))
      FOR DATA_MIRRORING (ROLE = ALL, AUTHENTICATION = Windows Negotiate, 
                          ENCRYPTION = REQUIRED ALGORITHM AES)
GO


http://www.ryanjadams.com/2016/01/change-availability-group-endpoint-ip/#axzz4yzaoZP8L

https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/change-the-ip-address-of-a-failover-cluster-instance