Should I just go to the airport WAY early and ask the desk staff before the security line to change the flight when I get there?

I have a 9:20pm flight from SNA to OAK today.
I want to change to a 4:10pm flight (also SNA to OAK) - 5 hours earlier

I bought a Wanna Get Away ticket at about $50 initially, but only $226 flight available now per the website/phone. When I called in they suggested the staff at the airport may have better / cheaper / free options to change the flight time instead.

Any suggestions or experience is must appreciated!