Re: Regarding(Read Replica in RDS) - Mailing list pgsql-admin

You can promote a Read Replica via AWS CLI or AWS Web Console.

Reference: 

• https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html#USER_ReadRepl.Promote
  
• https://awscli.amazonaws.com/v2/documentation/api/latest/reference/rds/promote-read-replica.html

aws rds promote-read-replica \    --db-instance-identifier test-instance-repl