The operator of a Holiday Inn Express in California must tell employees and union representatives in person that the company won’t interfere with employees’ rights to support a union.

The June 25 order came from the National Labor Relations Board, which also ordered Kalthia Group Hotels Inc. to bargain with UNITE HERE Local 49. The board found that the company had negotiated in bad faith about renewing a contract with Local 49 and tried to pressure employees at the Sacramento,...