I assume that you are talking about IPO.
No problem, Stock certificate will be issued and mailed to you provided that your application is successful (random drawing will be exercised if IPO is over-subscribed).
They will check against the cheque number and find out your clerical error.
No need to fill in a new form.
Anyway, if you fill in another form, you have to send a new cheque. That means you are sending two applications. Therefore, the former cheque will be processed.
If it is not IPO, again no need to send a new form and new cheque.