Add sub menu page in your plugin

this is how i am adding the menu and trying to add the sub menu page which is not adding.

party-reservation.php

function a_qoute_admin_action()
{
    add_menu_page(__('Reservations Pages'), __('Donation'), 'edit_themes', 'a-qoute', 'qoute_settings', ''); // working
    add_submenu_page("party-reservation.php", "Donations Log", "Donations Log", 8, "DonationsLog", "Donations_Log"); // not working.

}
add_action('admin_menu', 'a_qoute_admin_action');

if i use 'themes.php' it adds a sub menu page in the appearance section.