Hey @Bonza Dog Treats
Thanks for asking a really great question!
It will depend on the type of trigger you are using for your flow. If you are using a list or segment triggered flow, once a profile exits the flow it wont be allowed to go back into the flow. So if this is a welcome series flow triggered by your “Newsletter” list, once the profiles have exited, they will not be able to receive any of the emails that you have added back after deleting. If you are using a metric triggered flow, you can “add past profiles” and they will reenter the flow where they left off to receive the new emails.
From what you mention, offering a coupon and a followup to use it, it makes me think that this is a list or segment triggered flow. So my suggestion would be to create a new segment of profiles who received the previous flow and send them either a campaign with the updated email or create a new segment triggered flow for these customers to move through so they still receive the emails you wanted them to get.
I hope this helps!
OK thanks, that answers both points.