Thanks Leith Ross it works.
I have another issue also Turnaround time

Textbox8 = Textbox3-Textbox5 (This is to find no. of days)

Textbox9 = Textbox4-Textbox6 (This is to find no. of days) But i need to find difference between AM to PM & PM to AM.

Let say i received approval at 04:00 PM on 04/07/2012 and i have replied on 05/07/2012 09:05 AM. I have try it but failed.

Can you fix this also please.

Thanks for your help.