string RemoveNewsletterQueue(string accessKey, int listID, int newsletterID, int deliveryID, int scheduleID, booldeleteQueue)
accessKey: access key obtained using the LoginFromId method
listID: list identifier. Lists and corresponding IDs can be obtained calling the GetLists Method
newsletterID: ID of the message to be removed
deliveryID: ID of the delivery
scheduleID: ID of the schedule
deleteQueue: boolean value to indicate whether to delete the queue or not. If false, the message will be removed from the "messages in the sending queue"" or "scheduled messages", and moved to the "message waiting to be sent"