[JohnR]

She tried to keep it open, according to what is in Wikipedia

Many months before the expiration of the Military Bases Agreement of 1947 intense negotiations between the governments of the United States and the Philippines began. These negotiations resulted in the Treaty of Friendship, Peace and Cooperation between the United States and the Republic of the Philippines. This would have extended the lease of the American bases in the Philippines.

On September 13, 1991, the Philippine Senate rejected the ratification of this treaty, citing a number of reasons for the rejection. This was a devastating blow to the Aquino administration, who were strongly pro-treaty and even called for a referendum by the Filipino people; a move that was declared unconstitutional.
The American Flag is lowered and Philippine flag is raised during turnover of Naval Station Subic Bay.

In December 1991, the two governments were again in talks to extend the withdrawal of American forces for three years but this broke down as the United States refused to detail their withdrawal plans or to answer if nuclear weapons were kept on base. (Nuclear weapons were forbidden on Philippine soil.[citation needed]) Finally on December 27, President Corazon Aquino, who had previously fought to delay the U.S. pullout to cushion the country's battered economy, issued a formal notice for the U.S. to leave by the end of 1992. Naval Station Subic Bay was the U.S.'s largest overseas defense facility after Clark Air Base was closed.

http://en.wikipedia.org/wiki/U.S._Naval_Base_Subic_Bay