To cancel a driving test slot, visit your local Department of Motor Vehicles (DMV) website. Log in to your account, navigate to the 'Manage Appointments' section, and select the test slot you wish to cancel. Follow the prompts to confirm the cancellation. If you need assistance, contact your DMV's customer service for guidance. Remember, some states may have specific cancellation policies, so it's essential to check your local DMV's guidelines. Cancelling in advance can help others secure a slot, so it's a considerate practice.