Under Manage My Store, you'll find an option for Holiday Settings. Click on that and you can set your store to show a note at the top of listings which tells people you'll be away until X date and while people can still make a purchase, there'll be a delay in processing the order. You can also create an automated reply to any messages you receive.
The other option is to hide your listings, which means they remain active but won't show up in search results. Anyone who has something in their watch list can still see and access the listing, but if they try to make a purchase they see a note that the seller is not processing orders and the transaction is blocked.
