Hello,
thank you for reaching out to us with your post.

I guess you're referring to Standard ERP 8.4 2018-05-31

According to your description and sequence of steps:

- when closing and opening a Sales Order the message "Not allowed when an order is delivered" is shown, looks like a bug, please report.
- Unfortunately, there is no way. The opportunity to modify a Sales Order when it has been already invoiced would be a very good wish, please write it. We always try to streamline our functionalities according to Partner's pieces of advice and suggestions.

Best Regards
Giuseppe
HansaWorld Italy