At the time of purchase, a Reservation Order has one Reservation under it. Actions such as split, merge, partial refund, or exchange create new reservations under the Reservation Order.
I don't uderstand what do you mean?
The acymailing create multiple reservation order for one order, if admin or user make a change for order?
If yes, then this is wrong idea, because order in VM is only one (don't mather if I change order multiply).
Then better user own plugin definitelly, but who know? 🙂