Briefcase allows you to change the generated estimate number.
Mac
To modify the estimate number, Navigate to the estimate you need and whilst holding down the option/alt ⌥ key click on the estimate number. Once the dialog appears simply type in the new estimate number and press done.
Windows
To modify the estimate number, Navigate to the estimate you need and whilst holding down the alt key click on the estimate number. Once the dialog appears simply type in the new estimate number and press done.