If a customer’s client's workflow requires that the quote remains editable after being submitted for approval and notifications to must be sent to the approvers, this can be achieved by generating the notification e-mails when the quote is saved (rather than submitted). The basic concept entails creating a “Submit To” flag with “Yes”/”No”/null options and a PP price parameter table to keep track of the generated e-mails (to prevent the e-mails from being generated more than once).
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Create a calculation flow which will run this logic every 5 minutes (or as often as you and the client deem reasonable).
In case there are more than one approval level you will need to create a "Submit To" flag and a PP tracking table for each level.
The full code (including HTML formatting for the e-mail) is avaliable in Git - Copy_of_GenerateEmailOnQuoteSave_VA1.groovy