You can upgrade or downgrade a system with near-zero downtime using the following steps of migration:
* Open EC2 console
* Choose Operating System AMI
* Launch an instance with the new instance type
* Install all the updates
* Install applications
* Test the instance to see if it’s working
* If working, deploy the new instance and replace the older instance
* Once it’s deployed, you can upgrade or downgrade the system with near-zero downtime.
