All time off approvers will b able to view this information if relevant to their team and line reports.
As a time off approver you will have visibility of overlapping time off request during the approval stage of the request and also after it has been approved.
To view overlapping requests,
navigate to the location of the request in question
Click view to see the information relating to the request
expand the "overlapping events" section.
If there are any overlapping event the information will be listed there.
Easy as that! :)