I am trying to implement one functionality where logged in user can able to change the billing email address on the time of checkout. I have tried to do that but all the time it updates customer account email address which I don't want. I have tried by updating email from quote & order both before save order function using
$quote->getCustomer->setEmail(",,,,,") & $order->getCustomer()->setEmail("...") but unfortunately all the time it updates customer account email address but I need to update customer email id for particular order only (table- sales-flat-order).
Please suggest any solution.