Yes, biryani can be reheated. Store in the fridge for up to 3 days, then for best results reheat in the microwave. Heat for 2-3 minutes on high, stirring halfway through. It must be piping hot.  If you don’t have a microwave, you can reheat in a pan. Add the green biryani to a saucepan with 1-2 tsps of water, and warm it over a medium heat until hot through. Make sure to stir the rice so that the heat is evenly distributed.