How to modify blue/green switchover mapping

My MySQL 5.6 RDS cluster is reaching end of life. I've created a blue/green deployment, as suggested in the notification. When I attempt the switchover, it returns the message, "DB instance rl-dev-e1a has a different role than rl-dev-e1a-green-r0puam" the blue role is a writer instance and the green role is a reader instance. The blue e1b is a reader instance and the green e1b is a writer instance. It appears the mappings are crossed. How do I change the mappings, so that the blue writer is mapped to the green writer and the blue reader is mapped to the green reader?