The ghost should be directly spoken to and addressed thusly: "In the name of the Father, the Son, and the Holy Spirit, I command [or ask] you to tell me who you are and what you want".
This may have to be repeated three times.
Once commanded, the ghost should respond in a low and hollow voice, declare its satisfaction at being spoken to, and assure you not to be afraid, for it will do no harm.
This being the case, it commonly enters its narrative, which being completed, and its requests or commands given, with injunctions that they be immediately executed, it vanishes away, frequently in a flash of light; in which case, some ghosts have been so considerate as to desire the party to whom they appeared to shut their eyes.
During the narration of its business, a ghost must not be interrupted by questions of any kind; so doing is extremely dangerous: if any questions arise, they must be stated after the spirit has completed speaking.
Questions respecting its state, or the state of any of its former acquaintances, are offensive, and not often answered.
It is odd that ghosts do not go about their business like the living. In cases of murder, a ghost, instead of going to the law and laying out its information, or to the nearest relation of the person murdered, appears to a stranger who knows none of the parties or hovers about the place where his body is deposited.
However, it is presumptuous to scrutinize too far into these matters: ghosts have undoubtedly forms and customs peculiar to themselves.
If, after the first appearance, the persons employed neglect, or are prevented from, performing the message or business committed to their management, the ghost appears continually to them, at first with a discontented, next an angry, and at length with a furious countenance, threatening to tear them in pieces if the matter is not forthwith executed: sometimes terrifying them by appearing in many formidable shapes, and sometimes even striking them a violent blow. Blows given by ghosts have resulted in incurable injury.
It should have been observed that ghosts, in delivering their commissions, in order to ensure belief, communicate to the persons employed some secret, known only to the parties concerned and themselves, the relation of which always produces the effect intended.
The business being completed, ghosts appeal with a cheerful countenance, saying they shall now be at rest, and will never more disturb anyone. Thanking their agents, by way of reward, communicate to them something relative to themselves, which they will never reveal.