Types of Reserved Instances
Standard Reserved Instances can be purchased for one-year or three-year terms and applied to a single instance family, platform, scope, and tenancy over a term.
Convertible Reserved Instances can be purchased for a three-year term and exchanged for Convertible Reserved Instances with different instance families, platform, tenancy, or scope during the term.
Both Standard and Convertible Reserved Instances can be purchased to apply to instances in a specific Availability Zone, or to instances in a region. Reserved Instances purchased for a specific Availability Zone can be modified to apply to a region—but doing so removes the associated capacity reservation.
Convertible Reserved Instances can be exchanged for other Convertible Reserved Instances with entirely different configurations, including instance type, platform, scope, or tenancy. It is not possible to exchange Standard Reserved Instances in this way. It is not possible to modify the scope of a Convertible Reserved Instance once it has been purchased. For more information, see Modifying Your Standard Reserved Instances and Exchanging Convertible Reserved Instances.