The prayer answering system was created with a cross-pantheon evocation, and is designed to fulfill requests to a generic "god" or generic "I wish" statement. Prayers explicitly addressed with the sigil and addressed to the PAS are given extra priority. To use the PAS, open the sigil on the screen in front of you (or draw it on a piece of paper), stare into the star and state out loud "I pray to the prayer answering system for...". When using the PAS you may wish to also pass along an offering or payment, to be given to the prayer. The PAS is a "dumb" forwarding system, designed to forward your request to the entity that can help the most with your request. Therefore the PAS can be used to get in touch with the multitude of entities for which there are no names or sigils in existence.
Since the PAS forwards to the most applicable entity, you must be okay with any stranger of any particular alignment answering the call. It's best to keep things business-like with this system, and to give an offering as a gesture of goodwill.