$re = '/^(.+?)\. Last message: (.+\.?) (\w[^AMP].+?)\.$/mi';
$str = 'Sandy Smith. Last message: Will do! 2/2/17.
Caroline Doe. Last message: I will definitely tell him to come! Thank you so much for checking up on the both of us 2/2/17.
thundercall@ecnetwork.com. Last message: (Alert) CodeRED Weather Warning: The NWS has issued a Severe Thunderstorm Warning for your WALTHAM ST location from 8:00 AM April 30 until 8:30 AM April 3 4/30/16.
BFristN BLastN. Last message: Okay, I figured it out. Will post on the forum in a sec. 4:25 PM.
BFristN BLastN. Last message: Okay, I figured it out. Will post on the forum in a sec. Yesterday.
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php