post https://rest.cleverbridge.com/subscription/updatesubscriptionparameters
Updates one or more subscription parameters that pertain to a subscription. If the parameter key existed in the subscription, the parameter value will be overwritten. If the parameter key did not exist in the subscription, the parameter key and value pair will be created. The updates will be reflected on the next billing date.
For more information, see Track Performance of a Promotional Campaign for Subscription Customers. For XML examples and schemas, see the Additional Examples - Update Subscription Parameters.