Starbucks Pins Its Turnaround Hopes on 'Green Apron Service.' What Is It, Exactly? The coffee giant has made a spate of changes since CEO Brian Niccol took over last September.

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. Now, the service goes national.

Related: Starbucks Tells Employees to Return to the Office or Take a Buyout

It's all a part of the "Back to Starbucks" plan enacted by CEO Brian Niccol. 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?

The plan aims to improve the in-store customer experience after years of focusing on mobile and pickup orders.

"The strategy is to reconnect our partners with our customers," Chief Operating Officer Mike Grams told CNBC on Monday. "When you walk through that door, you're greeted with a smile. You are greeted again at handoff, a perfect cup of coffee ... and you're met with that connection."

The Green Apron and Back to Starbucks plans present a slew of changes, including a new dress code featuring the green aprons for baristas, upgraded interiors, writing names on cups again (which meant buying 200,000 Sharpies), ending its open-door policy for restrooms, cutting menu items, making drinks in four minutes or less, and more.

Starbucks also recently reduced the maximum allowed number of drinks for mobile orders, from 15 to 12, to help with speed during peak times.

Bloomberg previously reported that Starbucks is testing an algorithm to sequence mobile orders with pickup time slots.

Related: Starbucks Is Hiring In-Store Human Workers After Replacing People With Machines — and Finding It Didn't Work

Starbucks reports its latest quarterly earnings after the bell on Tuesday.

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