Do not assume you automatically have rights in the property in question.
You first need to look at the deed. If title was held by your father and his girlfriend as joint tenants, she now owns the entire property and you have no rights to it.
You also need to see if your father had a will, and whether you are the named beneficiary. If you are not, then you have no interest in the property.
Regardless, you have no right to diminish the girlfriend's interest in the property. You can only "step into the shoes" of your father.
You should meet with a probate lawyer in your area to discuss what rights you might have, and how you can proceed.
I agree with my colleague and changed the practice area from real estate to probate.
This is a question for a probate attorney - who would need to see the deed and information regarding other potential heirs of your father's estate.
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I agree with Mr. Perry. I would add that, under the bare facts you mention, it does not appear you have any rights to the property in his girlfriends name. You need an attorney to review title documents and any will or trust that your father executed before you can determine if you are entitled to anything by virtue of your father's death.
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