If you are an Approver or a Controller, you can assign a temporary approver or a controller to approve or control the expenses while you're out of office.
Here are the steps to add a temporary out of the office approver/controller,
Go to Profile > Personal Settings.
2. In Expense section of your profile settings, select Account Delegation.
3. Select the User whom you want to delegate your approval responsibilities to while you are away and enter the duration using 'Date from' and 'Date until'.
4. Click Add, to save the changes.
5. Once the new approver or a controller was added. The result will appear in the 'Your Out of Office Approvers' section.
Note: The appointed approver or a controller will receive an email notification that he/she was assigned as temporary approver or a controller.