how to change leave a comment text to something else like write a review

Hello sher21,
you can add the following to your child-theme functions.php changing the default parameters of the wordpress comment form:

add_filter('comment_form_defaults', 'my_comment_title', 20);
function my_comment_title( $args ) {
  $args['title_reply'] = 'Something';
  return $args;
}

hope this helps.

awesome now its working

previously i was using this code but when i updated customizr theme, function was not working

add_filter('comment_form_default_fields','alter_comment_form_fields');

function comment_reform ($arg) {
$arg['title_reply'] = __('Write a Review');
return $arg;
}
add_filter('comment_form_defaults','comment_reform');

closing this