# Rolling Back ECS Specifications Modification

#### Function

This API is used to roll back ECS specifications modification.

#### Constraints

After the rollback, the data modified during migration will be lost.

Before calling this API, ensure that the ECS status (which can be queried using the API for querying details about the ECS) meets the following requirements:

OS-EXT-STS:vm_state=resized

OS-EXT-STS:task_state=""

status=VERIFY_RESIZE

#### URI

POST /v2.1/{project_id}/servers/{server_id}/action

POST /v2/{project_id}/servers/{server_id}/action

Table 1 describes the parameters in the URI.

Table 1 Parameter description
Parameter | Mandatory | Description
--- | --- | ---
project_id | Yes | Specifies the project ID.
server_id | Yes | Specifies the ECS ID.

#### Request

Table 2 describes the request parameters.

Table 2 Request parameters
Parameter | Mandatory | Type | Description
--- | --- | --- | ---
revertResize | Yes | Null | Confirms the rollback of the ECS specification modification.

#### Response

None

#### Example Request

    POST https://{endpoint}/v2/{project_id}/servers/{server_id}/action
    POST https://{endpoint}/v2.1/{project_id}/servers/{server_id}/action

    {
        "revertResize" : null
    }

#### Example Response

None

#### Returned Values

See Returned Values for General Requests.

Parent topic: Status Management