Taking over the house means taking over the lease. You will then be able to serve a notice to quit as the original landlord's successor in interest.
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As the new owner of the property, you also become the landlord. If there is a lease, you will need to comply with its provisions. If not, then depending on how long they lived there and whether they are paying rent, you might be able to initiate the eviction process using a 3 day, 30 day or 60 day notice.