Section: 5.5.1.1 Calling party charging
Content: This applies to calling party pays in charged party principals defined in TS 22.115[ Service aspects; Charging and billing ]  [101]. For subscription related chargeable events the charging information shall indicate the charged party is normally the calling party. It should be possible for multiple leg calls (e.g. forwarded, conference or roamed) to be charged to each party as if each leg was separately initiated. However, in certain types of call, the originating party may wish/be obliged to pay for other legs (e.g. may also pay for the MT leg.). It shall be possible to change the chargeable party at the call set-up.