Can you re-potty train a dog?

I have adopted my daughters 3 year old Shepard who seems to have regressed in her potty habits. Since being with me (about a year) she has decided to do her business in the basement family room (no indication given she needs to go out). I have a 8 year old springer that she will go out with on a normal schedule (Minimum 3 times a day) but she still seems to sneak down and go down stairs. She is very smart and will let me know in the morning hours that she wants to go out but it seems the issue is in the afternoon or evening hours. Anyone have any thoughts?