David Christopher is out and Thomas Evans is in as chief executive officer of Tatum CIO Partners, a company that provides senior executives to firms on a temporary basis, as the company prepares to expand its operations.

Evans had been serving as chief marketing officer and co-managing partner.

Christopher, Tatum said in a statement, remains a partner and will focus on the firm’s public sector practice which it recently launched in Washington, DC.

Tatum CIO was launched in April of last year, has nearly 100 partners in 13 cities, and is modeled closely on Tatum CFO Partners which has been in business since 1993.