Charles Diggs Sr. recounted being denied accommodation at the hotel because he was African American.

In 1970, the historic thirteen-story limestone and brick structure was renamed the Olds Plaza following a sale to an Alma, Michigan oil businessman and subsequent renovation.

In 1974, however, a different Alma-based layer and entrepreneur purchased the property and renamed it again to the Plaza Hotel.

The renovation included the adaptive reuse of 290,000 square feet (27,000 m2) as well as a 40,000-square-foot (3,700 m2) addition and atrium, and earned the Showcase of Excellence Award from the Construction Association of Michigan in 1992.

A current project for the Romney Building includes the renovation of the brick plaza, new vestibules and entry doors, and the replacement of the second-floor deck.