Use action to modify a column that is a ref of another table

[MelBTP]

Hi, short version is I have 3 tables. Roles, Register Role, and New User
Roles has an ID, Role Name, Description
Register Role has ID, First Name, Last Name, Personal Email, and Role
New User has a lot of columns but Role is one of them.

Admin goes to form view to add a new registrant. they choose the user's role. 
When new user logs in with personal email they fill out a bunch of forms and at the end a bot sends an embedded app view email to admin who has an action button Approve that changes the Submit column in New User table to Approved. This is what i want to trigger an action that changes the Role column for that user in the Register Role table to a new Role (ID). But I continually get error saying i can't modify it. There are no valid if constraints, the column is editable, but is a ref, and I'm using the action set data for columns in this row to try and change the Role from 5 to 3. 5 is what the Admin put in during their form although they saw the Role name and not the id. Anyone know what i should do to accomplish this?

[MelBTP · Accepted solution]

Found the issue...system generated a computed key with Role and ID which was overriding the editability. I made the email the key and removed computed key as key and action no longer receives error.