After a part of a municipality is annexed to another municipality, any mayor, president, alderperson , trustee, clerk, treasurer, or attorney for the disconnecting municipality, who resides in the detached territory, shall continue in office as an officer of the disconnecting municipality until his successor has been elected at the next regular municipal election in this municipality and has qualified for office, or has been appointed and has qualified following this election.
65 ILCS 5/7-1-39