Just wanted to follow up. After they refunded my original charge, I made another Delta Comfort+ booking through the travel portal. When I tried to cancel through Delta directly, to get another e-credit, it kept giving me an error, so I canceled through the Capital One Travel portal and was easily able to get a credit. However, the travel portal won't allow you to book Multi-City trips or use existing Delta e-credits.

You also need to be careful when rebooking that you book Main Cabin or above to have the flexibility to make changes later. When I used my Capital One Travel credit to book new flights, it only gave me the option, unknowingly, to book basic economy. Luckily, I caught it and quickly called Capital One Travel at 844-422-6922 and she was able to put me back in Delta Comfort Plus. Once that happened, I tried again to cancel directly through Delta, so I could get an e-credit directly from Delta and have full access to ALL flights, including Multi-City.

Again it gave me an error. However, instead of canceling, I went to CHANGE FLIGHTS, after logging into my Delta.com account. Surprisingly, I was able to change flights and have full access to existing Delta e-credits, while also utilizing my Chase Ritz card for maximum travel protection.

A couple hours later, Capital One sent me an email:

"Your airline has modified your flights on your Capital One Travel booking XXXXXXXXX. Because Capital One Travel can’t see the changes made by the airline, we are not able to update your itinerary in My Trips.

Even though the portal still shows my canceled flight, everything on Delta,com reflects all the correct information.

Since Delta, and many other airlines, have made flight changes less onerous and punitive, it's extremely easy to utilize the Capital One Travel credit for full value, earning airline miles and elite credit.