How can I override a customer's shipping address for in-store pick up?

[builtbyvern]

We are trying to offer a buy online, pick up in-store option where a customer can buy from us, we deliver the product to a dealer of their choice for assembly, then they pick that up. Sales tax must be calculated based on store pick up location and not the customer's shipping address. This is where I'm getting very stuck.

Is it possible to override a customer's personal shipping address in checkout? We have a dealer selector they use and we pass the address in as a metafield to checkout, but for the life of me I can't see how any extension or function available can enforce a) no editing of the shipping field, and b) passing in the address of the dealer as the shipping address. Am I approaching this incorrectly? Is this possible?

[DavidNZSSI]

Hey there! I know this involves another app (so may not be ideal for you), but you can do this in our app Starshipit:

1. Set up your dealers as pick up locations in Starshipit.

2. Create a rule so that if a customer chooses one of the dealer pick up locations, that becomes the location they get sent to pick up from.

All the best in any case, happy to discuss more if you're interested.