How do you change coolant in a citroen Picasso?

To change the coolant in a Citroën Picasso, first ensure the engine is cool and then locate the coolant reservoir. Open the reservoir cap and drain the old coolant by removing the drain plug at the radiator's bottom or using a siphon. Once drained, flush the system with water if necessary, then refill with the appropriate coolant mixture, making sure to bleed the system of any air by running the engine and checking for any leaks. Finally, dispose of the old coolant properly.