Simplify the following text for a Grade 13 native English-speaking person.
Original: On 11 December 2007 she became the first woman in Australia 's history to be in the prime ministerial role , by assuming the role of acting prime minister while Kevin Rudd attended the United Nations Climate Change Conference in Bali .
Simplified: On 11 December 2007 she became the first woman in Australia 's history to be in the prime ministerial role when she became acting prime minister while Kevin Rudd went to the United Nations Climate Change Conference in Bali .