Can an AWS EC2 AMI be replaced with the same ID?

Is it possible to replace a custom AMI with a new one while retaining the original AMI Image ID? Reason I asked this is I have various Cloudformation templates that spin up auto-scaling EC2 groups. Instead of having to go through the process of updating my Cloudformation template with the new AMI Image ID and reloading I would simply like to terminate the running instances which would make new instances start up. This "terminate instances" approach would work if I could replace an AMI and keep the same Image ID. Any thoughts?