Complex sentence: She was a member of the Aam Aadmi Party's National Executive but left the party in May 2014 to join the Bharatiya Janata Party on 16 January 2015.
Split into simpler sentences: She was a member of the Aam Aadmi Party's National Executive but left the party in May 2014. She joined the Bharatiya Janata Party on 16 January 2015.