When your computing needs change, you can modify your Reserved Instances and continue to benefit from your capacity reservation. You can modify your whole reservation or just a subset in one or more of the following ways:
Switch Availability Zones within the same region
Change between EC2-VPC and EC2-Classic
Change the instance type within the same instance family
Availability Zone and network platform modifications are supported for all product platform types. Instance type modifications are supported only for the Linux platform types. However, due to licensing differences, Linux Reserved Instances cannot be modified to RedHat Instances. For more information about RedHat pricing, see Amazon EC2 Reserved Instance Pricing.
Modification does not change the remaining term of your Reserved Instances; their end dates remain the same. There is no fee, and you do not receive any new bills or invoices. Modification is separate from purchasing and does not affect how you use, purchase, or sell Reserved Instances.
After modification, the pricing benefit of the Reserved Instances is applied only to instances that match the new parameters. Instances that no longer match the new parameters are charged at the On-Demand rate unless your account has other applicable reservations.
When you modify a subset of your reservation, Amazon EC2 splits your original Reserved Instances into two or more new Reserved Instances. For example, if you have Reserved Instances for 10 instances in us-east-1a, and decide to move 5 instances to us-east-1b, the modification request results in two new Reserved Instances—one for 5 instances in us-east-1a (the original Availability Zone), and the other for 5 instances in us-east-1b.
The following topics guide you through the modification process: