I bought a Latitude fare ticket online on the AC website. If I cancel the ticket online, and then book a new ticket, will I be able to use the credit from the cancelled ticket to pay for the new one, online? ... or will I have to talk to an AC agent?

Only reason I ask is that (as you know) doing stuff online will take me 2 min whereas talking to an Agent will take more like 20-30 minutes.

Thanks