First, please note this process was used prior to Change Orders being implemented.
Getting back to an "unaccepted" Quote
When a Project is Created from a won Opportunity, the accepted Quote is locked from edits and cannot be changed from the Project. To make changes to the accepted Quote you will need to delete the won Opportunity's Project.
Save a copy of your signed Proposal (optional)
In the following steps we will be unaccepting the signed Proposal. If you would like to keep a permanent record of this Proposal we recommend saving a copy of the approved Proposal as a PDF which you can upload as an attachment to the Quote.
Delete the Opportunity's Project
Begin by navigating to the Project that was created when the Opportunity was won. Then, choose the "Delete" option from the Project's "more" menu.
Please be aware that you are deleting the Project so any changes made (accounting, ordering, etc.) will be lost.
Go back the Opportunity
Now you will need to locate the won Opportunity which has been automatically moved to its previously "un-won" stage in the Opportunities area of Cloud and open the Opportunity's detail view.
Change the Quote's Status
From the Opportunity's detail view, navigate to the Accepted Quote. Using the Quote Ribbon Notification in the Quote's header you can change the status of the Quote to non-accepted state. Once the status is changed, the Quote is now ready for changes.
After making your changes the quote can be presented again to the customer.