Oct 22 (Reuters) - Walmart Inc"s (WMT.N) U.S. corporate workers will start working at the retailer"s offices from Nov. 8 after more than a year and a half, a company memo showed on Friday. The big-box retailer, one of the largest employers in the United States, said employees would work at its campus offices on a more regular basis, with all of them expected to be fully vaccinated or have an approved accommodation in November. "There is no substitution for being in the offices together — it helps shape our culture, collaborate, innovate, build relationships and move faster," Chief People Officer Donna Morris said in the memo. Walmart"s global tech team, however, will primarily work virtually. Rival Amazon.com Inc (AMZN.O) will let individual teams decide for how many days corporate employees would be expected to work from office in a week, Chief Executive Officer Andy Jassy said in a message to employees earlier this month.