$re = '/(^[A-Za-z0-9 \"]*)(\<sip:)([\+1]*8004001506)(.*\>.*)/m';
$str = '"WIRELESS CALLER" <sip:+18004001506@192.168.18.40;isup-oli=62>;tag=gK0461bc7f';
$subst = "\"Company A\" \2\3\4";
$result = preg_replace($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