See Removing a Product and follow the instructions based on your WSDL version.

You must set the ContractEffectiveDate and EffectiveDate fields (and also the ServiceActivationDate and CustomerAcceptanceDate fields if enabled) to the correct date to ensure there are no refunds, credits or prorations.

Set the contract effective, effective, service activation and customer acceptance dates to the date you want the cancellation or downgrade to take effect.

• To insure no proration, this should be the first day of the next invoice period or the first day of the next term, depending on if you want to downgrade at the end of the last invoice period or end of term.

• For example, If the current invoice period for the product extends from 10/01/2011-10/31/2011 and the next invoice period for this product begins on 11/01/2001, set the contract effective date to 11/01/2001.

When the Remove Product amendment is successful, follow the steps for Adding a Product , using the date used in the Remove Product amendment.