This update action can only be used if a Customer is not assigned to the Cart.
If a Customer is already assigned, the Cart uses the Customer Group of the assigned Customer.
To reflect the new Customer Group, this update action can result in [updates to the Cart](/api/carts-orders-overview#update-a-cart). When this occurs, the following errors can be returned: [MatchingPriceNotFound](ctp:api:type:MatchingPriceNotFoundError) and [MissingTaxRateForCountry](ctp:api:type:MissingTaxRateForCountryError).
This update action can only be used if a Customer is not assigned to the Cart. If a Customer is already assigned, the Cart uses the Customer Group of the assigned Customer.