When I edit an entry I only see a Duplicate and Cancel button.

When you open a time entry you can make adjustments to the entry as long as it's not on a finalized invoice.

If you open an entry and it shows only a Duplicate and Cancel button that means the entry is on a finalized invoice and can not be edited or deleted.

However, at the top right it will show the status of the entry and Invoice # it's attached to, so you could go to the invoice itself to make the changes you need:

1. Go to to Invoicing - Find Invoice
2. Type in this invoice number and click Search.
3. Click the desired invoice and click the "Unfinalize" button to place the invoice back to a Pre-bill state*
4. Scroll down and click the desired entry to make the changes you need and re-save it
   
5. Click Finalize again to re-finalize your invoice

 *Please note, if you make any changes to the hours, amounts, or delete the entry, your invoice total will change.