More musical chairs announced at the Federal Communications Commission on Tuesday.

Rick Kaplan, senior legal adviser to FCC Chairman Julius Genachowski, will leave his position to head the agency’s wireless bureau.

Ruth Milkman, current wireless bureau chief, will move to the chairman’s office in a new new position as special counsel for “innovation in government.”

The moves, effective June 20, come as the FCC considers a mega $39 billion merger proposed by AT&T and T-Mobile. The FCC has appointed a committee, separate from the wireless bureau, to oversee the agency’s review of the proposal.

Kaplan has served as Genachowski’s chief legal adviser for about a year and during the review of Comcast’s joint venture with NBC Universal.

“He has played an integral part in the Commission’s policymaking over the last year – especially in the area of wireless communications – and he will bring that experience to bear as chief of the Wireless Telecommunications Bureau,” Genachowski said.

Milkman has led the wireless bureau since August 2009, as the communications industry focuses on wireless spectrum as the foundation of mobile broadband access.

In her new job, she will “lead a team to develop proposals for procedural, regulatory and statutory changes to further innovation,” the agency said in a press release.

“With Ruth Milkman as chief, the Wireless Bureau has reached new heights in spectrum policy development and thought leadership in the area of auctions,” Genachowski said.