Within a users settings it is possible to control who a submitter is allowed to submit an expense report to for approval. You might have multiple approvers on your account for different departments/teams/offices so it is possible to restrict which approver each submitter can submit their reports to. Whether it's to keep the approval process within a team/office or to restrict 'friends' approving everything for each other without actually checking.
This is done very easily under the users permissions on the settings page. Just click on 'All People' to the top right in AutoEntry and click 'Edit' to the left of the users name and then the settings tab across the top.
You can now select which approver this specific submitter can submit their expense reports to:
Multiple approvers can be selected so when submitting a report for approval, the submitter can select which approver they're submitting the report to.
Once submitted, an Approver can re-assign to a different approver if the report has been submitted to the wrong Approver using the 'Reassign' button in the submitted report.