Originally Posted by flyerCO

This time HUCA worked for you. However I'm betting agent handled it as if it were a schedule change, not a voluntary change on outbound. If the price was the same for changed flights, they likely figured this was an acceptable work around. It really wasn't, as you should've paid an increase in fare for return flights. Point being the agent did you a huge favor by going outside of policy and likely saved you $$$ in process. Don't expect this in future.

As noted above, for domestic tickets there's no cost difference between OW and RT. Domestic RT nowadays is simply 2 OW fares.. If there's a schedule change on one ticket (say must travel day later or you cancel and request refund due to change) DL will allow you to change the 2nd ticket by a day or request a refund also. (Not all airlines will do this, but DL will)