Originally Posted by
hi55us
It's actually valid on a round trip (and now is valid on two one ways, they now deposit 2 one way vouchers that can be used separately).
Unfortunately you are completely shut out of using the voucher if you want to ride in a sleeper.
I recall reading somewhere that it is possible to book with the companion in coach, and later upgrade to a sleeper. I'm trying to find where I saw this information, but am curious whether anyone has been successful doing this.