Hi ceraulo,
I'll show you how to do this, but I want to make sure you understand the process here. When you create a change from an RITM, the RITM is stored in the parent field of the change_request. This means 2 things 1) you can show the Parent field on the change request form to see the RITM and since it's a reference field you can click through to the RITM, and 2) there's only going to be one RITM per change request created this way, so a related list is not ideal, but this can still be done if the parent reference field is not what you're looking for.
Go to System Definition -> Relationships in the left nav. Create a new record. Name it whatever you want to appear as the Related List name. Applies to table = change_request. Queries from table = task. Your Query with script will simply be this.
(function refineQuery(current, parent) {
current.addQuery('sys_id', parent.parent);
})(current, parent);
Now you can configure your change request form to add your new related list.
