http://www.rfc-editor.org/rfc/rfc5789.txt
RFC 5789: PATCH Method for HTTP, L. Dusseault, J. Snell2010-03-01T23:00:00-00:00Several applications extending the Hypertext Transfer Protocol (HTTP) require a feature to do partial resource modification. The existing HTTP PUT method only allows a complete replacement of a document. This proposal adds a new HTTP method, PATCH, to modify an existing HTTP resource. [STANDARDS-TRACK]