The Government may sublet any part of the premises but shall not be relieved from any obligations under this lease by reason of any such subletting. The Government may at any time assign this lease, and be relieved from all obligations to Lessor under this lease excepting only unpaid rent and other liabilities, if any that have accrued to the date of said assignment. Any assignment shall be subject to prior written consent of Lessor, which shall not be unreasonably withheld.