RegEx Pattern: \[\d(?:\d|)\/\d(?:\d|)\/\d(?:\d|) \d(?:\d|):\d(?:\d|):\d(?:\d|)(?: PM| AM|)]
[dd/mm/yy hh:mm:ss] Person 1: message content [dd/mm/yy hh:mm:ss] Person 2: message content
[dd/mm/yy hh:mm:ss PM] Person 1: message content [dd/mm/yy hh:mm:ss AM] Person 2: message content
[(m:mm)/(d:dd)/yy hh:mm:ss] Person 1: message content [(m:mm)/(d:dd)/yy hh:mm:ss] Person 2: message content
[(m:mm)/(d:dd)/yy hh:mm:ss PM] Person 1: message content [(m:mm)/(d:dd)/yy hh:mm:ss AM] Person 2: message content