I've met a problem that I can't quite figure out how to resolve.
Our app provides delivery to local pickup points in stores and other facilities. This means, that resulting shipping address is not client's home address.
When client completes an order, they receive an email from Shopify with incorrect shipping address (their home address). This happens because email is sent instantly after order is completed, leaving us no chance to react to it with webhooks and API.
Leaving this problem as is will produce confusion for purchasers.
One solution I thought of is to utilize write_checkout permission and edit shipping address just before client completes their order on Shopify store page. However, it is not possible for carrier service apps to use this permission scope.
Shopify support forwards me to the forums, so here I am. It would be great if someone pointed me into the right direction.