Usually we handle your scenario by having an alternate location or contact details on the incident form and maintain the truth or permanent info for the user on the user table. If you multiple incidents per user how do you know which is the latest?
Anyways if you want to update reference fields you need to do so as per the example above, you have to query the referenced table via Glide Query to the sys_user table, filter via query the user record you want to update and then specify the value.
Show me the code you have written thus far and I will assist you.
Conrad
