I do not generally perform card tricks or "on demand" for reasons previously posted on several forums, but ...

this does not mean I am not prepared for either request. An example from Thanksgiving might be of value here.

My brother has been trying to get me to teach some magic tricks to home-schooled teenagers of several friends. I might.
We were at Thanksgiving at his home and I knew that several of these families would be there also.

It was planned that after supper many would engage in playing Tripoley that involves both cards and chips.
We could not stay, but I guessed that some magic request might evolve form the setting.
I stood close-by as one father shuffled the cards - then the request.

I announced, "I prefer not to do card tricks, but would be interested in any that you folks can do." Glances all around.

Then I said, "Allow me to get things started for you." I took the deck and cut in into four piles. Then turned over the top cards to reveal the four Aces.

I asked, "Can any of you do a trick with those?" In the demonstrations that followed I got a feeling for what the prospective students felt/knew about magic.
....

several ways of doing this that most of you may know. The key is being prepared. Yes, I had previously removed the Aces in anticipation.