Elastic IP Address : Delete /Disassociate

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html

https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Scenario4.html

1st Disassociate Elastic IP Address

then Release Elastic IP Address

if Elastic IP is not bound, its chargeable