$re = '/(?<=says\sto)[\s\S]*?(?=\(\d{4}-\d{2}-\d{2}\s(\d\d:){2}\d{2}\s\w{2}\s\w{3}\))/m';
$str = '(2021-07-04 11:58:43 PM BST)
---
len wee zim (Tradition (US) ) says to yohan sen
[[:Conversations will be recorded and may be monitored by the participants and
their employers:]] Hi yohan
(2021-07-05 12:04:42 AM BST)
---
len wee zim (Tradition (US) ) says to yohan sen
okay -5 / 0 .
(2021-07-04 11:47:14 PM BST)
---
Ke Cho Ki says to
Hano Cho
hello
(2021-07-05 12:09:41 AM BST)
---
len wee zim (Tradition (Asia)) says
to yohan sen
yes -5 / 0 TN -- / +2.5
---
* * *
Processed by wokl Archive for son malab | 2021-07-05 12:26:44 AM
BST
---';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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