Add one or more new instances to an existing recurring iCalendar object.

Cancel one or more instances of an existing iCalendar object.

Used by an Attendee to negotiate a change in an iCalendar object. Examples include the request to change a proposed event time or change the due date for a task.

Used by the Organizer to decline the proposed counter-proposal.

Used to publish an iCalendar object to one or more "Calendar Users". There is no interactivity between the publisher and any other "Calendar User". An example might include a baseball team publishing its schedule to the public.

Used by an Attendee to request the latest version of an iCalendar object.

A reply is used in response to a request to convey Attendee status to the Organizer. Replies are commonly used to respond to meeting and task requests.

Used to schedule an iCalendar object with other "Calendar Users". Requests are interactive in that they require the receiver to respond using the reply methods. Meeting requests, busy-time requests, and the assignment of tasks to other "Calendar Users" are all examples. Requests are also used by the Organizer to update the status of an iCalendar object.