Starbucks has begun training for its "Green Apron Service," which aims to bring a more familiar feel to customer service interactions. On Tuesday, Starbucks reported its sixth consecutive quarter of declining sales. Starbucks told CNBC Monday that a pilot run of its "Green Apron Service" in 1,500 stores showed numerous improvements, including increased sales. In June, Niccol told Reuters that the "Green Apron" model for service and staffing would be implemented in all stores in North America before the end of the summer. What Is Green Apron Service?