First, disable all plugins related to FeedBurner or remove the settings before proceeding. Common plugins include FeedSmith, FeedBurner FeedSmith Extend, FD FeedBurner Plugin, and WordPress FeedBurner Plugin.
Log in to FeedBurner and find the RSS feed for the show that you want to redirect. Once you've selected the correct show, press the "Edit Feed Details" button:
Add your RSS.com feed to the "Original Feed" field and click "Save Feed Details"
After you've confirmed that your FeedBurner feed is redirecting properly to RSS.com, you can then select the "Delete Feed" button.
Check the box that says "With permanent redirection" and push "Delete Feed." This process will put a 301 redirect on the FeedBurner feed, effectively telling apps and platforms to use the RSS.com feed instead.