Concepts and technologies are described herein for managing recurring appointments without losing historical data associated with the recurring appointments. In accordance with the concepts and technologies disclosed herein, a recurring appointment definition can be modified without deleting the recurring appointment definition and/or losing exceptions, notes, and/or other data associated with the recurring appointment definition. Additionally, the concepts and technologies disclosed herein allow the modification of an existing recurring appointment definition without creating a new recurring appointment definition. Thus, synchronization between rules-based calendaring applications and expansion-based calendaring applications can be accomplished without creating multiple instances of related recurring appointments created due to modifications of the recurring appointment definition.