To contact an actor for participation in your project, call the Actor Locate number above and press the button for "To contact an actor with an offer for work ... (or something to that affect)".   You will be allowed to have three names searched during one call.  Make sure you have the actors name spelled correctly and a pen or pencil to jot down the info.  Act professional and you will be treated like a casting director or producer, usually the types that call.   The Actor Locate service will give you the name and phone number of a contact person for the actor.  It could be their agent (if they're very active) or their attorney or personal manager.   The latter two are more ideal, since indie producers typically don't have a "pay-or-play" offer to propose.  And, the latter two are also interested in broadening the range of projects for their clients, something that agent's may not be concerned with.   Agents typically will open up a calendar and say "When? For how long? and For how much?"  If you can't answer these questions, pray that the contact person isn't their agent.  Good luck.