Call flow consists of many small phases such as Drop,Play Sound,Record Sound,MonitorDigits,GatherDigits,Generate Digits,Send Fax,Receive Fax,Call Transfer,Data Access.The phases are arranged in an flow tree.Each type of phase has each own son phases.For example Play Sound phase has one son phase-OnDone,indicating the case that the sound has beenn played.You can change a phase to another type of phase to change the call flow.For example,the default type of the OnDone phase of the play sound phase is of the Drop type.Just click the Drop phase,and then click an icon indicating gathering phase on the tool box to change it to a gathering phase.