By their nature "companion" tickets require simultaneous use of the paid and additional ticket. This means you would pay for two and have one at reduced cost. (Companion tickets are seldom "free", there are fees and taxes.) However, after a period of flying you should accumulate sufficient miles for an award ticket, in which circumstance you might redeem one award, pay for one plus a companion, if you are fortunate enough to find award and companion availability on the same flights.