Mail Script - How to get the first name of the variables reference type

[GwynethPhoS]

I need my notification email body to show the first name based on the email of a supplier contact. I have two reference field, i need to get the first name of both variables to be shown on my email notification. anyone could help me with this? thank you in advance. and its not reference to a sys_user.

[GwynethPhoS]

tried to make mail script but this is the preview of my email: Dear, Email script render error: email script [ getOffboardedFirstName ] does not exist , Email script render error: email script [ getDelegatedFirstName ] does not exist.  need to get the first name of offboarded user (reference to sn_slm_contact_m2m_supplier) and delegated task to first name (also reference to sn_slm_contact_m2m_supplier). i have a record producer for this.