Stop email confirmation from 3PL fulfillment center

Hello,

I build an API integration for Shopify and 3PL, the integration is working fine, however the client does not want for the 3PL to send shipment confirmation since the client is already sending the tracking information to the customers.

Where can I remove that option? I checked the API scopes that I selected for the API integration, but I do not see any related to shipment confirmation.

I am trying to stop the first email conformation from the 3PL and just leave the shipment confirmation from the client.

Thanks for the help!