how to perform edit service provider and cost via Rest API

Summary:

What parameter should be sent to change service provider and cost via Rest API, i need example of the payload i have to send

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What parameter should be sent to change service provider and cost via Rest API, i need example of the payload i have to send ( I am using Flutter for mobile development) and 1 - how to change the shipment status via API call.
2 - how to trigger an automation agent via API.

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