Pass variable value back to calling function -Easy

VS 2005, VB.NET I have the following function:

public sub getmethodid(sopnum,custid)
which calls the following function and passes the sopnum string variable:
     validateOrder.itemcount(sopnum)  the code for this function follows:

Module validateOrder

    Public Sub itemcount(ByVal sopnum As String)

        Dim cn As New SqlClient.SqlConnection()
        Dim cmd As New SqlClient.SqlCommand()
        Dim ad As New SqlClient.SqlDataAdapter
        Dim strcn As String
        Dim strSQL As String
        Dim itmcnt As New DataSet
        Dim row As DataRow
        Dim vop10200cnt As String

        strcn = My.Settings.STRL
        cn.ConnectionString = strcn

        strSQL = "select count(*) as cnt from vop10200 where sopnumbe = '" + sopnum + "'"

        cmd.CommandText = strSQL
        ad.SelectCommand = cmd
        ad.SelectCommand.Connection = cn
        ad.Fill(itmcnt)

        cn.Close()

        For Each row In itmcnt.Tables(0).Rows

            vop10200cnt = (RTrim(row.Item("cnt")))

            If vop10200cnt = 0 Then

                Dim tableid As String = 1
                orderLog(sopnum, tableid)

sopnum = "no go"  <--------  here I am attempting to change the sopnum variable to "no go" but it does not change when passed back to getmethodid function, how can I send back the new variable value?


            Else
                getd10200cnt(sopnum, vop10200cnt)
            End If
        Next

    End Sub