how do i send a long sms exceeding 160 characters using AT command

Dim isSend As Boolean = False
Try
    Dim recievedData As String = ExecCommand(port, "AT", 300, "No phone connected")
    recievedData = ExecCommand(port, "AT+CMGF=1", 300, "Failed to set message format.")
    Dim command As [String] = "AT+CMGS=""" & PhoneNo & """"
    recievedData = ExecCommand(port, command, 300, "Failed to accept phoneNo")
    command = Message & Char.ConvertFromUtf32(26) & vbCr
    recievedData = ExecCommand(port, command, 3000, "Failed to send message")
    '3 seconds
    If recievedData.EndsWith(vbCr & vbLf & "OK" & vbCr & vbLf) Then
	isSend = True
    ElseIf recievedData.Contains("ERROR") Then
	isSend = False
    End If
    Return isSend
Catch ex As Exception
    Throw ex
End Try