How do we connect FedEx and UPS accounts in a development environment

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We are trying to make some site improvements and have made a copy of our shopify site live site. When we go to deploy the changes, what happens to the existing FedEx and UPS checkout options that are currently working in our live site? Is there a way to just move the front end changes live without disturbing the back end freight shipment methods? Where can I see this configuration for the live site and who can I talk to at shopify to make sure we don't crash our site by overlaying the shipment and rate configuration?