Amazon Elastic Compute Cloud
User Guide for Linux Instances

Submitting Modification Requests

AWS provides you with several ways to view and work with modification requests: You can use the AWS Management Console, interact directly with the Amazon EC2 API, or use the command line interface.

AWS Management Console

Each target configuration row on the Modify Reserved Instances page tracks the number of instances for the current instance type (Count) and the instance size footprint of your reservation relative to its instance type (Units). For more information, see Understanding the Instance Size Footprint.

If you have specified either more or fewer Reserved Instances than are available for modification, the allocated total is displayed in red. The total changes to green and you can choose Continue after you have specified changes for all the Reserved Instances that were available for modification.

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 reservations for 10 instances in us-east-1a, and decide to move 5 instances to us-east-1b, the modification request results in two new reservations: one for 5 instances in us-east-1a (the original Availability Zone), and the other for 5 instances in us-east-1b.

To modify your Reserved Instances using the AWS Management Console

  1. Open the Amazon EC2 console at

  2. On the Reserved Instances page, select one or more Reserved Instances to modify, and choose Modify Reserved Instances.


    The first entry in the modification table is the original, unmodified reservation. To modify the attributes of all reservations, choose new specifications from the menus. To modify or split only some of your reservations, add an additional line for each change.

  3. Choose Add for each additional attribute change and enter the number of reservations to modify for Count.

  4. To change the Availability Zone, select a value in the Availability Zone list.

  5. To change the network platform, select a value in the Network list.

  6. To change the instance type, select a value in the Instance Type list.

  7. To delete a specified attribute, choose X for that row.


    If the Modify Reserved Instances page contains only one row for attribute changes, you cannot delete that row. To modify multiple Reserved Instance attributes, first add a row for the new specifications and then delete the original row.

  8. Choose Continue.

  9. To confirm your modification choices when you finish specifying your target configurations, choose Submit Modifications. If you change your mind at any point, choose Cancel to exit the wizard.

Command Line Interface

You can complete modification tasks programmatically by using the AWS CLI (modify-reserved-instances), the AWS Tools for Windows PowerShell (Edit-EC2ReservedInstance) the Amazon EC2 API (ModifyReservedInstances), and the AWS SDK for Java.

Amazon EC2 API

You can use the ModifyReservedInstances action to modify your Reserved Instances. For more information, see Amazon EC2 API Reference.

Determining the Status of Your Modification

You can determine the status of your modification request by looking at the state of the Reserved Instances that you are modifying. The state returned shows your request as in-progress, fulfilled, or failed. Use the following resources to get this information:

The following table illustrates the possible State values in the AWS Management Console.

State Description

active (pending modification)

Transition state for original Reserved Instances.

retired (pending modification)

Transition state for original Reserved Instances while new Reserved Instances are being created.


Reserved Instances successfully modified and replaced.


New Reserved Instances created from a successful modification request.


Original Reserved Instances after a failed modification request.


If you use the DescribeReservedInstancesModifications API action, the status of your modification request should show processing, fulfilled, or failed.

If your modification request succeeds:

  • The modified reservation becomes effective immediately and the pricing benefit is applied to the new instances beginning at the hour of the modification request. For example, if you successfully modify your reservations at 9:15PM, the pricing benefit transfers to your new instance at 9:00PM. (You can get the effective date of the modified Reserved Instances by using the DescribeReservedInstances API action or the describe-reserved-instances command (AWS CLI).

  • The original reservation is retired. Its end date is the start date of the new reservation, and the end date of the new reservation is the same as the end date of the original Reserved Instance. If you modify a three-year reservation that had 16 months left in its term, the resulting modified reservation is a 16-month reservation with the same end date as the original one.

  • The modified reservation lists a $0 fixed price and not the fixed price of the original reservation.


The fixed price of the modified reservation does not affect the discount pricing tier calculations applied to your account, which are based on the fixed price of the original reservation.

If your modification request fails:

  • Your Reserved Instances maintain their original configuration.

  • Your Reserved Instances are immediately available for another modification request.

For more information about why some Reserved Instances cannot be modified, see Requirements for Modification.