Mr Niccol is also streamlining Starbucks' menu and changing its ordering algorithms to optimise the handling of mobile, drive-thru and in-store orders.
Last autumn, Starbucks brought in Mr Niccol to boost sluggish sales figures.
Starbucks' global same-store sales, a measure of sales at locations open for at least a year, dipped 2% in its 2024 fiscal year, which concluded on September 29.
"Our intent is to operate more efficiently, increase accountability, reduce complexity and drive better integration," Mr Niccol penned in his memo.
"Our size and structure can slow us down, with too many layers, managers of small teams and roles focused primarily on coordinating work," Niccol explained.
