I'm looking at a return ticket from Catania, Italy to San Francisco. Air Malta 641 to Swiss Air 1791 to UA/Swiss Air codeshare UA 9728.

The ticket is on UA stock and makes a plane change in Zurich with a 50 minute layover to catch the long leg to SFO.

Once I start my outbound travel from SFO on UA, can I call the Government desk, have them take over the reservation, and ask that the Zurich/SFO return leg be pushed to the next day, essentially giving me a 24h 50m stopover in Zurich?