Hello again @fabienne_florian
Yes, this is simple. As previously mentioned, you need to use the action HTTP Reqeust to contact the Sailpoint BETA API get-entitlement and modify your Workflow to look like this.
You then use the API to search for the entitlement with ID {{$.trigger.accountRequests[0].attributeRequests[0].attributeValue}}
and extract its name from the response body, and change the email accordingly.
See this show and tell for full reference on how to perform this HTTP Request.