NEW YORK, July 20 (Reuters) - UAL Corp. , the parent of United Airlines, is close to renegotiating the terms of its interim financing package to double the amount of cash available and extend the maturity to next summer, The Wall Street Journal reported on Tuesday. UAL also is trying to enlist a new lender, General Electric Co.'s GE Commercial Finance, to join in the proposed $1 billion debtor-in-possession financing, the newspaper said, citing unspecified people with knowledge of the situation. UAL's existing lenders, J.P. Morgan Chase & Co. <JPM.N>, Citigroup Inc. and CIT Group Inc. , are also in negotiations to participate, the Journal said. The idea would be to syndicate the expanded loan to the same 30 financial institutions that participated in the earlier financing, and possibly more, according to the newspaper. Last month, the U.S. government rejected United Airlines' third and final bid for a loan guarantee, forcing the carrier to move forward with its efforts to secure financing on its own to exit bankruptcy. The new $1 billion facility, which could be finalized as early as Thursday, would not come due until June 30, 2005, the Journal said, citing people familiar with the negotiations. The current, smaller financing package matures at the end of 2004. A UAL representative was not immediately available to comment on the report, nor were representatives of GE, J.P. Morgan Chase, Citigroup or CIT.