I don't know how things work elsewhere, but here if a sole examiner goes on vacation, they generally make arrangements with another examiner/examiners to cover their work. You let your major clients know you will be gone, and who to call in your absence.  Whoever you hire checks your faxes, e-mail and overnights for any surprises from clients that did not get the message.  When you get back you pay them and then bill your clients.  We have six examiners in our company and we do this all the time for sole practitioners.  It has to be someone you trust to give your client the product they expect.  I think this is the best thing one can do, the client can't be expected to just stop working while their examiner in vacationing.