What is the difference between Delegate and Out-of-office Approver?

Adding a delegate will authorize another user to create, submit, and approve reports on your behalf. The delegate will be able to access your Zoho Expense account and perform actions on your behalf.

An Out-of-office approver will not have access to your Zoho Expense account. If you’re going on a vacation or caught up with business travels, you can assign an approver to approve transactions. All the transactions submitted to you will be auto-forwarded to the assigned approver.