Currently, the way LawVu users handle vacation time is they simply hand over their pressing matters to one of their colleagues by adding them to the matter or making them matter manager, owner, or contract owner.
A temporary hand-over facility specifically for vacations is on our development radar, so look out for this in the future.
You may be aware that you can reassign your matters in bulk from within your profile. When you reassign all your matters to someone else you actually don't lose visibility on those matters, however, you would have to reassign those matters to yourself one-by-one once you returned. This really doesn't make it an effective solution.
For those matters on which you are the matter manager or owner, you also have the option to assign a delegate. For more information on delegates check out this article.