Student or Learner
The hotel said the suite is usually reserved for high rollers but is available for booking if lying vacant.
1. what is the meaning of high roller in the above sentence?
2. if lying vacant means if the suite is vacant. Am I correct?
(Not a Teacher)
1) A high roller is someone who bets big (and often loses big) on the casino floor. Casinos typically give such people preferential treatment at their hotels, bars, and entertainment venues.
2) Yes. You could also say "if it lies vacant" as well.