In order for the usual approval workflow to progress without issues, the first approver will need to approve and then process the claim. Once they click on the Process button they will be able to select the next approver and submit it to them.
The first approver will need to follow the steps below:
Log in and click the Notifications icon (triangle icon in the top right corner).
Click the claim approval request in the menu on the left.
Click Process.
Select the next approver and click Submit.