Legal Question in Landlord & Tenant Law in Pennsylvania

Try www.ilrg.com and see if there is a notice to vacate. Here is the link:

http://www.ilrg.com/forms/vacate.html

Indicate that the tenant was permitted to remain in the property, that you are now desiring to sell and give the tenant time to get out. While the time is generally short for a tenancy at will, as a realistic matter, this is (a) your daughter and (b) its just not that easy to pick up and find another place to live. I would be reasonable and give 30 days or by the time of closing.