Uber has announced it will make various changes to how its drivers get paid, including adding an option for riders to tip their driver.

Tipping is available as of today in Seattle, Minneapolis, and Houston; the cities will serve as test markets that let the company “create the best tipping experience.” Tipping will be available to all US drivers by the end of July.

Other significant changes include shortening the cancellation window—the time period during which a rider can cancel without penalty—from five minutes to two minutes. Drivers will also begin to collect a per-minute rate for wait times if a rider keeps them waiting longer than two minutes after arrival.