A client may not need all the calendar properties of a calendar object resource when presenting information to the user. Since some calendar property values can be large (e.g., ATTACH or ATTENDEE), a client can choose to restrict the calendar properties to be returned in a calendaring REPORT request to those it knows it will use.
However, if a client needs to make a change to a calendar object resource, it can only change the entire calendar object resource via a PUT request. There is currently no way to incrementally make a change to a set of calendar properties of a calendar object resource. As a result, the client will have to get the entire calendar object resource that is being changed.