Referencing a Contact with VLOOKUP

edited 12/09/19 in Smartsheet Basics

I have an employee list that has a column for "supervisor", which is a "Contact" type column, allowing the selection of a supervisor from a pre-defined list.

I have another sheet, a time sheet, which needs to reference that supervisor column with vlookup so that approvals can be sent to that person for hours logged. It must be a "Contact" type column to allow the column to be used in the approval request rules ("Send an approval request o" -> "Contact in column"). However, it seems like I can't use vlookup in a Contact type column - it returns "#INCORRECT ARGUMENT SET". 

Is what I'm trying to do not possible?