[John Klasen]

when on a call there seems to be no way of correcting numbers

[hallux]

Correcting what numbers? If you want to access your contacts to modify someone's phone number, press your home key, enter your unlock code (if needed) then locate your contacts or people app to modify the number in question.

[John Klasen]

when on a call how do you delete a number - this is needed when you input credit or account numbers

[hallux]

Are you talking about the dial-pad inputs to prompts on the phone? Just like on a landline, there's no going back, the tone is sent as soon as the number is pressed.

[John Klasen]

yes when prompted for instance to touch 1 for english then input your account number you need to delete the 1

[hallux]

You don't actually. The numbers get sent as they get pressed and then just sit in the window doing nothing more but showing the history of numbers pressed on that call