Speak directly to the entity, or in the room most affected, saying:
It is time to leave here; all is well. There is nothing here for you now, You
must be gone
Go now, go ~ complete your passing, Go, and with our blessing fare well.
Remove everything of the previous occupant ~ writing and photos in particular.
If there is anything you wish to keep, purify it with salt or incense, saying:
With this I purify you of the past, of hurt and memories,
keeping only Love.