Public IP needs to converted as Elastic IP

Hi There

Unfortunately you will not be able to convert an auto-assigned public IP to an Elastic IP. See https://aws.amazon.com/premiumsupport/knowledge-center/ec2-associate-static-public-ip/

You might also consider moving this instance behind an Elastic Load Balancer. This provides the added benefits of using additional services like auto-scaling. You will also not need to worry about pubic IP addresses because the load balancer handles it for you. See https://aws.amazon.com/what-is/load-balancing/ for more info.