Menu callback; present a form for deleting a date type.
function system_delete_date_format_type_form($form, &$form_state, $format_type) {
$form['format_type'] = array(
'#type' => 'value',
'#value' => $format_type,
);
$type_info = system_get_date_types($format_type);
$output = confirm_form($form, t('Are you sure you want to remove the date type %type?', array(
'%type' => $type_info['title'],
)), 'admin/config/regional/date-time', t('This action cannot be undone.'), t('Remove'), t('Cancel'), 'confirm');
return $output;
}