Error message in User Exit

Hi All,

I wish to put in an error message on a user exit that gets displayed when the user clicks SAVE if the PO Number is blank.

I can get the error message to appear but I want the user to be able to change the PO number after the message appears but the screen is all grey.

Is there anyway I can let the user change the PO Number after the error message has been displayed in the user-exit?

Many Thanks,

Colm