Change external store ID - Store Management - Mercado Pago Developers
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Change external store ID

There is also the possibility to create an external ID (external_id) for a certain store. This field is optional, but can be used as an identifier for the order management software system.

To enter the value of an external ID in a store, perform a PUT sending the store_id and access_token (generated by the OAuth authentication process) to the endpoint /proximity-integration/stores/{StoreID}/ external_id. See Security for more information about OAuth.

You will also be able to consult the information of a store through its external ID. For that, just send as request parameters the user_id related to the store, the external_id and the access_token. Check more information in the API Get store by external ID .