Complex sentence: On 21 November 2007, Brown was announced as the new manager of Dumbarton; the following day, however, it emerged that Brown had turned down the post due to personal reasons.
Split into simpler sentences: On 21 November 2007, Brown was announced as the new manager of Dumbarton. On November 22, however, it emerged that Brown had turned down the Dumbarton post due to personal reasons.