The answer is no. As in "no coverage". You can trade trips starting on the same day or for more days, but you cant trade trips for different days.

When line holders say that dropping the reserve part of the extension doesn't affect them, I tell them that this is how it does. My buddy at Delta says they can drop and move whatever they want because they went after the company about this no coverage non sense. In September, DCA320 FO, 30 reserves in a base of 120 pilots, but no coverage? Please...