Hitman: Blood Money

You have to make sure you haven't been discovered at all or the play may not go on. Make sure you have taken the pistol from your jacket in the beginning.

You also have to take the prop pistol, put it in your inventory, press and hold A to choose "Set down Real WWI pistol." You can't have both on the table.

After that, wait and the guy will shoot him for you. Alternatively, you can knock out the actor, hide him, then play his part and shoot Alvaro D'Alvade yourself.

i need to know exactly what you did prior to switching the gun, because you may have done something, to make the actors no longer perform

if you got a gold account i can walk you through it step by step over Live

GT: Biggest Gunns

All you must do is take the fake gun and place the real gun. Then, go down to the theater and watch the show. Eventually, he will shoot. It takes some time.

After you have the gun and get into his room, hide in the closet. Eventually, he will walk in for a break. During this time he will leave for the bathroom (or something). Use this time to quickly switch the prop with the real gun. If you are quick enough you can walk out of the room before he notices you. If not, just hide in the closet until he is called back for the scene.

Alternatively, like TearsofBlood said, you can knock-out the actor,, suit his clothes, and then act out the scene yourself with the real pistol. I tried this, however, and didn't know what to do and they discovered me.

They've pretty much given you the answer. Here's a good vid for it. (remove the spaces)

http://www.youtube.com/ watch?v=j6iJS28_Law&feature= PlayList&p=B9DA6997C3BA8A43&index=2