Hello @rafael_merces 

You can just go to the REST API Explorer and select Namespace as "global"  and API Name as "user_role_inheritance". Just paste the SyS_id of the user in the column "user_sysid" and hit on "Send". You get the response with the details. 

 

https://www.servicenow.com/docs/csh?topicname=user-role-inheritance-api.html&version=latest