Situation: Sarah and Ann have been friends for a long time and they work at the same place. They met very often and were close enough to consider each other a good friend. Ann, however, started behaving a bit strange recently. She started not wanting to meet Sarah as often, and she started coming to work less often. They were on the same project, so that meant that she started not doing her part, which Sarah had to cover up. Sarah also heard that she said a few bad things about her to other colleagues. She did not use to speak about anyone before, so this came as a surprise.
Question: How should Sarah behave? Should she finish her friendship with Ann? Should she stay unresponsive on the assumption that this is temporary? If you think this is a situation that can be solved, how should Sarah help with it?