American asset management firm Blackstone Group has reached an agreement to restructure approximately $7bn of the remaining debt tied to its 2007 purchase of Sam Zell's Equity Office Properties Trust, reported the Wall Street Journal.

According to the report, under the Equity Office deal, which is expected to be finalized by year’s end, the maturity of the debt will be extended to 2014 from 2012.

In exchange, Blackstone will pay down the $7bn debt by 10% and the interest rate on the remaining debt will increase by one percentage point, the newspaper quoted its sources as saying.

In the other deal, Blackstone reworked the balance sheet of Hilton Worldwide, the firm’s single-largest investment, cutting Hilton’s $20bn debt load by nearly $4bn, the Journal noted.

The deal represents the latest chapter in the story of Blackstone’s purchase of Equity Office for $39 billion, including debt and equity.