Change from dropbox to interview

I am eligible for dropbox H1B. when I submitted my application I wrote old passport number on my visa doc profile. I cannot submitted documents because of this issue. I sent an email on cgi for passport number update. it has been 6 days but no update. I am thinking about changing my dropbox to interview appointment. do I have to pay fee again for this ?
any body have any experience?

You can cancel and reschedule using same fee reciept up to 5 times.