# ModifyInstanceEventWindow
<a name="API_ModifyInstanceEventWindow"></a>

Modifies the specified event window.

You can define either a set of time ranges or a cron expression when modifying the event window, but not both.

To modify the targets associated with the event window, use the [AssociateInstanceEventWindow](API_AssociateInstanceEventWindow.md) and [DisassociateInstanceEventWindow](API_DisassociateInstanceEventWindow.md) API.

If AWS has already scheduled an event, modifying an event window won't change the time of the scheduled event.

For more information, see [Define event windows for scheduled events](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/event-windows.html) in the *Amazon EC2 User Guide*.

## Request Parameters
<a name="API_ModifyInstanceEventWindow_RequestParameters"></a>

The following parameters are for this specific action. For more information about required and optional parameters that are common to all actions, see [Common Query Parameters](CommonParameters.md).

 **CronExpression**   
The cron expression of the event window, for example, `* 0-4,20-23 * * 1,5`.  
Constraints:  
+ Only hour and day of the week values are supported.
+ For day of the week values, you can specify either integers `0` through `6`, or alternative single values `SUN` through `SAT`.
+ The minute, month, and year must be specified by `*`.
+ The hour value must be one or a multiple range, for example, `0-4` or `0-4,20-23`.
+ Each hour range must be >= 2 hours, for example, `0-2` or `20-23`.
+ The event window must be >= 4 hours. The combined total time ranges in the event window must be >= 4 hours.
For more information about cron expressions, see [cron](https://en.wikipedia.org/wiki/Cron) on the *Wikipedia website*.  
Type: String  
Required: No

 **DryRun**   
Checks whether you have the required permissions for the action, without actually making the request, and provides an error response. If you have the required permissions, the error response is `DryRunOperation`. Otherwise, it is `UnauthorizedOperation`.  
Type: Boolean  
Required: No

 **InstanceEventWindowId**   
The ID of the event window.  
Type: String  
Required: Yes

 **Name**   
The name of the event window.  
Type: String  
Required: No

 **TimeRange.N**   
The time ranges of the event window.  
Type: Array of [InstanceEventWindowTimeRangeRequest](API_InstanceEventWindowTimeRangeRequest.md) objects  
Required: No

## Response Elements
<a name="API_ModifyInstanceEventWindow_ResponseElements"></a>

The following elements are returned by the service.

 **instanceEventWindow**   
Information about the event window.  
Type: [InstanceEventWindow](API_InstanceEventWindow.md) object

 **requestId**   
The ID of the request.  
Type: String

## Errors
<a name="API_ModifyInstanceEventWindow_Errors"></a>

For information about the errors that are common to all actions, see [Common client error codes](errors-overview.md#CommonErrors).

## See Also
<a name="API_ModifyInstanceEventWindow_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/ec2-2016-11-15/ModifyInstanceEventWindow) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ec2-2016-11-15/ModifyInstanceEventWindow)