You can't. According to official website and Yuxi CDC, the health certificate is handled by Yuxi CDC. According to the Notice of Yuxi CDC on Matters Related to Employees Handling Health Certificates, Yuxi CDC is closed on public holidays and holidays, and will not handle health certificates during May Day. Yuxi City, Yuhe River, named after water, is a prefecture-level city under the jurisdiction of Yunnan Province, located in the middle of Yunnan Province.