If you are having the approval process, only the approving authority can approve the concession request. If the approval mechanism is not there, Principal or the system admin can approve the concession request, by following the below path

Finance --> Approvals --> Approve Concession Requests --> Select the Academic year, Location and click on Get --> Click on the number under the pending column against the Branch name --> Select the student and click on "Approve/Reject" --> Update the Concession amount (If you want to make the changes) and update the remarks --> Click on Approve to process the concession (or Click on Reject to reject the concession request)