How to get order status updated with a 3rd party fulfillment centre using Custom API?

[MarkGa]

We are using a 3rd party fulfillment centre to ship our orders. But the order status is not changing to Fulfilled after they ship an order. Our store is connected to them using a Private App.

They've told me that Shopify need to approve the Admin API permissions so that "Fullfillment Services" is set to "Read and Write".

How do i get Shopify to approve /make that change? Or is this something that needs to be done from their end?