22.214.171.124 PUT Method
Clients use the PUT method, as specified in [RFC2518] section 8.7, to create new Calendar objects or update existing Calendar objects in the Calendar folder. To add new Calendar objects, another user, or a new resource, the PUT request is sent to the address for that user or resource's calendar. The PidTagExchangeNTSecurityDescriptor property ([MS-OXPROPS] section 2.687) is used to restrict access to Calendar folders for resources.
As specified in [RFC2518] section 8.7.2, the PUT method cannot be used to create new collections, only resources.