OK you can filter comment default text like this
it will get you very close
add_filter( 'comment_form_defaults', function ( $defaults ) {
if ( is_single( 129243 ) ) {
$my_defaults = array(
'comment_field' => sprintf(
'<p class="comment-form-comment">%s %s</p>',
sprintf(
'<label for="comment">%s</label>',
'Prayer'
),
'<textarea id="comment" name="comment" cols="45" rows="8" maxlength="65525" required="required"></textarea>'
),
'title_reply' => 'Say a little prayer',
'title_reply_to' => 'Give your blessings to %s',
'cancel_reply_link' => __( 'Cancel' ),
'label_submit' => __( 'Submit your Prayer' ),
);
$defaults = array_merge( $defaults, $my_defaults );
}
return $defaults;
} );
You will need to change the number here to the specific POST ID that you want to change
if ( is_single( 129243 ) ) {