If you are an Approver or a Controller, you can assign a temporary approver or controller to approve or control the expenses while you're out of the office. 

Here are the steps to do this:

1. Go to Profile > Personal Settings. 
2. Select the Out of office approver page. From here you can select the user to whom you want to delegate your approval responsibilities while you are away, and enter the duration of your absence.
   
3. Click Add and fill in the information on the pop-up.
   
4. Click add approver to save the new approver. The result will appear in the Out of office approvers section. 
   

Note: The appointed approver will receive an email notification that he/she was assigned as a temporary approver.