Originally Posted by
ChrisA330
No, you can not move to any flight that still has seats for sale. You can't change to an overbooked flight even though that flight still may have seats available for sale....
Originally Posted by Jebby_ca
Please also keep in mind that it is a Same Day Airport change... that can be done via the online check-in tool, or by the agent at the airport. If you call in to make a change (unless you are calling a concierge), they'll ask for the change fee + fare difference.
Exactly the way the Same-day change for fee program is explained online. It is a check-in process not offered via the call centre nor online, save the options offered via web check-in. That the OP was able to bully his way, calling the Agents rude because they correctly said no, is unfortunate.