sentences:  Although Senate presidents are elected at the start of each Congress, there had been numerous instances of Senate coups in which a sitting Senate President is unseated in the middle of session.Term-sharing agreements among senators who are both eyeing the position of the Senate President also played a role in changing the leadership of the Senate, but in a smooth manner, the peaceful transition of power and this was done two times in 1999 and in 2006.Unlike most Senate presidents that are the symbolic presiding officers of the upper house, the Senate President of the Philippines wields considerate power by influencing the legislative agenda and has the ability to vote not just in order to break ties, although the Senate President is traditionally the last senator to vote.