Datepicker plugin - date question

Datepicker plugin - date question

Hi there, I've been given the task of modifying an existing booking calendar for a hotel. I didn't code it initially and I am admittedly not a jQuery/Javascript coder so my language may be off. 

The booking calendar can be seen here:  http://www.thelistelhotel.com/ (top right dropdown, in red)
Essentially, the powers that be would like for the "check out" calendar date to default to the day after the date chosen for "check in". I have tried various 'minDate' and 'maxDate' configurations to no avail. 

The current code is (I believe) just the basic datepicker script. It looks like this:

$(document).ready(function() {
    $("#datepicker").datepicker();
      $("#datedepart").datepicker({ minDate: +1 });
});
Can anyone tell me what the syntax needs to be in order to solve the problem above?

a simple solution would be most appreciated.