In order to make modifications/overwrite the default php.ini settings do the following:

1) In public_html create a php.ini file with the changes you desire i.e.:

max_execution_time=200
max_input_time=200

For Windows Server
extension=php_pdo.dll
extension=php_pdo_mysql.dll

 

Linux Server
extension=pdo.so
extension=pdo_mysql.so

2) In public_html in a .htaccess file add the following:

suPHP_ConfigPath /home/domaine_username/public_html/

Replace domaine_username with the client's cPanel username