We may be reaching here, but we have an issue with our Black Friday sales, where we offer hourly flash sales on certain items. Due to the limited capacity, customers must buy these items or miss our entirely. Some customers order multiple times throughout the day, and they are charged shipping ($29.99) each time they checkout. Due to the flash sales, they cannot wait to place one order.
Is there any app or method to use Shopify that allows for a waiving of shipping costs if the customer has already ordered? Or perhaps an app that allows customers to edit existing orders immediately, rather than email us with their requested changes?