To reuse an order that was created on accident, press F8 amend and then change the account number to a 0 and press enter.  You will get a series of prompts to remove the parts and labor from the order.  Follow the prompts and then the next time that user creates a new order they will be prompted to reuse that untitled order.  Only reuse them when prompted. By Re-using orders you limit the amount of Gaps between numbers for audit purposes.

Below is what you will see after the Order is changed to "Untitled"