In the documentation , it is explained how to delete and access_key but it seems not to work.
See :
Example Delete an Access Key
This REST API example demonstrates how to delete a CA SDM access key.
The following example shows the request:
DELETE /caisd-rest/rest_access/1201703106 HTTP/1.1 Host: hostname
The following example shows the response:
HTTP/1.1 204 No Content Content-Type: application/xml;charset=UTF-8 Content-Length: 0
Release : 17.X
Component : CA ServiceDesk Manager.