You can add your vacation time from the settings->Vacation tab.
You can also add your auto vacation email kind of "Hi, We are on vacation now." When any person raise a ticket while you are on vacation then they will have an auto email.
You will find a notice on the new ticket page. So, who will create a ticket, they will find that you are not available or if still they created a ticket they will get auto email reply So, they acknowledged your vacation and help you to enjoy your vacation.
Thanks for choosing Auxilium support desk,