prob with graph type in crystal report

HI VB experts

i have small prob is, i was designed crystal report with chart control. i am calling that report from vb with crystal control. now what i want is i need to change graph types like bar, line , pie .
so i need to send parameters, can anybody help me pls

this is my code

Printer.Orientation = vbPRORLandscape
Cr_Risk1.Connect = "DSN = " & Gvr_dsn & ";UID =" & Gvr_sql_uid & ";PWD =" & Gvr_sql_pwd & ""
Cr_Risk1.ReportFileName = "c:\megsreports\GraphRetnAnls.rpt"
Cr_Risk1.SQLQuery = "SELECT rp_desc_retn,rn_retn_level, rn_gnpi_retn FROM crstb_retn_detail,crstb_risk_master where rp_risk_num=rn_risk_num and rn_risk_num='RP00001'"


Cr_Risk1.WindowState = crptMaximized
Screen.MousePointer = vbDefault
On Error GoTo ErrorHandler
Cr_Risk1.PrinterDriver = vbPRORLandscape '
Screen.MousePointer = vbDefault

Cr_Risk1.Action = 1

Exit Sub
ErrorHandler:
MsgBox Cr_Risk1.LastErrorString