CHARLOTTE, N.C. — Tansukh Ganatra, a co-founder of telecommunications provider US LEC, will take over as the firm’s chief executive officer on an interim basis, the company said Tuesday.

Ganatra, who is a member of the US LEC board, will replace current CEO Aaron Cowell. Cowell’s departure was expected. He had announced plans to leave the company when US LEC agreed to merge with PAETEC Corp.

The merger was expected to be closed this quarter but is now not expected until the first quarter of next year, US LEC disclosed in a statement. The companies announced the merger in August.

When the deal is completed, the combined company will be publicly traded under US LEC’s stock ticker (NASDAQ: CLEC). PAETEC is privately held. The merger is valued at $450 million.

Ganatra founded US LEC along with Richard Aab in 1996. Aab is the firm’s chairman. Ganatra has been actively involved in the merger implementation, US LEC said.

Arunas Chesonis, founder of PAETEC, has known Ganatra for many years, US LEC said. Chesonis will serve as chairman and CEO of the combined company.

“Mr. Chesonis is very supportive of Mr. Ganatra serving as interim CEO of US LEC,” Aab said in a statement. “Mr. Chesonis told me that he looked forward to working with his old friend to complete the planned merger and integration process.”

Ganatra served as president and chief operating officer of US LEC from 1996-1999 and then became CEO. He retired in 2001.

US LEC offers a variety of telecommunications services to businesses in 16 eastern states.

Cowell had been CEO since 2002.