A method of controlling user changeable IP Multimedia Subsystem, IMS, service rules associated with a user of a user equipment, UE, wherein the service rules are defined within an Extensible Markup Language, XML, document and maintained within the IMS network, the method comprising: requesting the service rules associated with the user from an XML Data Management Server, XDMS, over a Ut interface of the IMS network; receiving, over the Ut interface, the XML document or a fragment thereof comprising one or more informational elements identifying whether a corresponding service rule is changeable by the user of the UE, wherein at least one of the informational elements corresponds to at least one of an unconditional or immediate based service rule, the information element(s) for said at least one unconditional or immediate based service rule including an indication that specifies the conditions for whether changes to said at least one unconditional or immediate based service rule is allowed and/or disallowed, and wherein the indication comprises either a first value indicating the corresponding service rule is changeable by the user or a second value indicating the corresponding service rule is not changeable by the user of the UE; interpreting said informational elements and said indication(s) for said at least one unconditional or immediate based service rule, and displaying to the user on the UE whether the corresponding service rules are changeable by the user of the UE; receiving user defined service rule information, wherein the user defined service rule information include changes to the service rules associated with the user of the UE; and transmitting to the XDMS, over the Ut interface, the user defined service rule information for use by the IMS network in updating the service rules associated with the user of the UE. requesting the service rules associated with the user from an XML Data Management Server, XDMS, over a Ut interface of the IMS network; receiving, over the Ut interface, the XML document or a fragment thereof comprising one or more informational elements identifying whether a corresponding service rule is changeable by the user of the UE, wherein at least one of the informational elements corresponds to at least one of an unconditional or immediate based service rule, the information element(s) for said at least one unconditional or immediate based service rule including an indication that specifies the conditions for whether changes to said at least one unconditional or immediate based service rule is allowed and/or disallowed, and wherein the indication comprises either a first value indicating the corresponding service rule is changeable by the user or a second value indicating the corresponding service rule is not changeable by the user of the UE; interpreting said informational elements and said indication(s) for said at least one unconditional or immediate based service rule, and displaying to the user on the UE whether the corresponding service rules are changeable by the user of the UE; receiving user defined service rule information, wherein the user defined service rule information include changes to the service rules associated with the user of the UE; and transmitting to the XDMS, over the Ut interface, the user defined service rule information for use by the IMS network in updating the service rules associated with the user of the UE.