Request a Medallion upgrade assignment by logging onto the Delta website at delta.com. Provide your SkyMiles program number and your PIN. Follow the prompts to check the availability of upgraded seats for your flight.
Purchase an upgrade certificate from third party sellers. Look for such offers online at independent classified advertisement sites -- examples would be craigslist.com or local newspaper online classifieds. Verify with Delta the authenticity of the certificate before purchasing to avoid unwanted surprises.
Purchase the seat upgrade directly through Delta. Fees vary depending on the flight. Ask for the upgrade when at the airport as Delta charges a surcharge for buying the upgrade with a telephone representative of the company.
