Top Position in position management expecting approval

Summary:

Our top position errors if they try and carry out an approval task

Content (required):

Hi

We use the position hierarchy although we don't have a position tree (we do use an org. tree though). Our top position doesn't have a parent position.

Our approval rule for absence as an example uses management hierarchy (set up by Oracle).

However, if our top position books leave etc there is an error as HCM is expecting an approver - which there isn't as this position is at the top of the organisation.

Apologies if this has already been covered somewhere but could you please advise how to resolve this?