Pratibha Patil, presidential candidate of the ruling United Progressive Alliance (UPA)-Left-Bahujan Samaj Party combine, on Thursday submitted her resignation as Rajasthan governor.
"I have submitted my resignation to President (APJ Abdul) Kalam," Patil told reporters after a brief meeting with him at the Rashtrapati Bhavan in New Delhi.
"I thanked him for the help and guidance he gave me," she said.
If elected, the 72-year-old Patil will be the first woman president of the country.
While the UPA-Left-BSP have the majority share of the votes, the Bharatiya Janata Party (BJP)-led National Democratic Alliance had thrown its weight behind Vice President Bhairon Singh Shekhawat.
But after the regional United New Progressive Alliance (UNPA) mooted Kalam's name for a second term, the BJP and some of its allies expressed their willingness to support Kalam if there was "consensus" on his name.
But NDA member Shiv Sena is not ready to prop up Kalam, who indicated on Wednesday to UNPA leaders that he was willing if there was "certainty" about his re-election.
The UPA-Left-BSP has 570,000 votes in the electoral college comprising MPs and MLAs that elects the president.
The NDA has 354,689 votes and the Third Front 105,225.