# POST Ad Avail State: Start or Stop Ad Avail on a Channel
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Start or stop the ad avail blanking on a channel.

The channel must be running to change the ad avail state. To check the status, use GET Channel. For information on the status, see [Channel Status Elements](monitoring-manage-channels.md#monitoring-manage-channels-status).

## HTTP Request and Response
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### Request URL
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```
POST http://<Conductor IP address>/channels/<channel ID>/ad_avail_state/start
```

or 

```
POST http://<Conductor IP address>/channels/<channel ID>/ad_avail_state/stop
```

### Call Header
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+ Accept: Set to application/xml
+ Content-Type:Set to application/xml

If you are implementing user authentication, you must also include three authorization headers; see [Header Content for User Authentication](header-content-user.md).

### Response
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A response is only given if you POST to a channel that is not running or that does not have avail blanking enabled.