Currently, LawVu users can hand over their workload to colleagues by adding them to their matters and contracts so they'll be a member, or make their colleague the Matter Owner, Matter Manager, 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 maintain visibility. However, since you would have to reassign those matters to yourself one-by-one once you return, 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.