My initial reply when I was in that situation was " At this moment in time I do not know the answer to your question but I know where to find it, I will get back to you within 24 hours."
Then ask in the forum or look in the training or just search for it.
Before you are in the situation of being asked you do need to let ALL your team (PSAs and CSAs) know you are there for them and will help to the best of your ability.
