This
is one of the commonest reasons I am initially called in whether
you believe in the afterlife or not, pause just for a moment,
you may not have to use a professional to sort this one out.
Without
going into the complexities of why this works, simply try asking
the ghost to leave first with absolute conviction. So simple but
more often than not they will oblige.
The
presence of ghosts will usually mean you have earth energy within
your house so a check on this would be advised whether your ghost
is friendly or not.