We need to exclude a specific person from the Expense approval rules, please suggest attribute.

We have a requirement to exclude CEO from the Expense approval hierarchy. To achieve so we are trying to exclude CEO's user from the approval rule. I am trying to use the below attribute in the advance mode, where I have two questions:

1. in the condition what details should I enter about the Expense report owner: User ID, Person ID or Person name?
2. While entering any of the above details am getting validation error which says : "RUL-05720: data type mismatch for test "!=": List != String"

Please suggest your insights on these doubts.

Also if there is any other way to exclude a specific person from the approval hierarchy, please suggest.