How do you reset a flat tire warning on a BMW 645Ci?

To reset the flat tire warning on a BMW 645Ci, first ensure that all tires are properly inflated. Then, turn on the ignition without starting the engine. Navigate to the vehicle settings using the iDrive system, select "Tire Pressure Monitor," and choose the option to reset or initialize the system. Follow any prompts to complete the reset, and then check to confirm that the warning light has turned off.