• Amazon's cloud boss Matt Garman told employees in an all-hands meeting that if they don't agree with its new five-day in-office mandate, they could leave for another company.
• The company announced the new policy last month. Employees have until Jan. 2 to adhere to the new policy.
• Roughly 37,000 employees have joined an internal Slack channel created last year to advocate for remote work and share grievances about the return-to-work mandate, according to a person familiar.

Amazon's cloud boss on Thursday gave employees a frank message about the company's recently announced five-day in-office mandate.

Staffers who don't agree with Amazon's new policy can leave, Amazon Web Services CEO Matt Garman said during an all-hands meeting at the company's second headquarters in Arlington, Virginia.

"If there are people who just don't work well in that environment and don't want to, that's OK, there are other companies around," Garman said, according to a transcript viewed by CNBC. "At Amazon, we want to be in an environment where we are working together, and we feel that collaborative environment is incredibly important for our innovation and for our culture."

Amazon has observed that working in-office helps teams be more collaborative and effective, a company spokesperson told CNBC.

Garman's comments were reported earlier by Reuters.

Amazon announced the new mandate last month. The company's previous return-to-work stance required corporate workers to be in the office at least three days a week. Employees have until Jan. 2 to adhere to the new policy.

The company is forgoing its pandemic-era remote work policies as it looks to keep up with rivals Microsoft, OpenAI and Google in the race to develop generative artificial intelligence. It's one of the primary tasks in front of Garman, who took over AWS in June after his predecessor Adam Selipsky stepped down from the role.

The move has spurred backlash from some Amazon employees who say they're just as productive working from home or in a hybrid work environment as they are in an office. Others say the mandate puts extra strain on families and caregivers.

Roughly 37,000 employees have joined an internal Slack channel created last year to advocate for remote work and share grievances about the return-to-work mandate, according to a person familiar with the matter who asked not to be named because they weren't authorized to speak to the press..

At the all-hands meeting, Garman said he's been speaking with employees and "nine out of 10 people are actually quite excited by this change." He acknowledged there will be cases where employees have some flexibility.

"What we really mean by this is we want to have an office environment," said Garman, noting an example scenario where an employee may want to work from home one day with their manager's approval to focus on their work in a quiet environment.

"Those are fine," he said.

Garman said the mandate is important for preserving Amazon's culture and "leadership principles," which are a list of more than a dozen business philosophies meant to guide employee decisions and goals. He pointed to Amazon's principle of "disagree and commit," which is the idea that employees should debate and push back on each others ideas respectfully. That practice can be particularly hard to carry out over Amazon's videoconferencing software, called Chime, Garman said.

"I don't know if you guys have tried to disagree via a Chime call — it's very hard," Garman said.

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