Be honest, just say "I'll have to get back to you on that one", we can't all know everything :-)

I always say early that good questions are answered quickly, great questions require more effort, It's always best to know what you don't know. Besides it gives you a chance to get back together with that person again and another chance to impress.

"I don't know, but I'll look that up at the next break and get back to you."

The only technique is to be honest and say you don't know, but you will find out the answer and get back to them as soon as possible. Training is almost as much about learning as it is about teaching.

Nop! Only thing one can know in this matter that the answer of "is their" is "there is not"!!!