From a legal standpoint it really depends on where you live. You'll have to check the laws in your State to find out how long a person, that has given no notice of leaving, has to be gone before you can consider her moved out.
You stated that she only left 2 or 3 things in her room. Are all her clothes gone? All her personal items? If so, then I think that's a pretty good determination that she doesn't plan to come back. But just to make sure you can legally take her name off the mailbox, check your local renters laws.
Good luck. I don't envy your position. It's never easy to try to evict someone, especially when that person is family.
issue is, she doesnt want to leave. she knows shes going to but shes playing really dirty. reciving actual eviction notices and saying she never got them. leaving for a few days at a time, but this time shes been gone over 2 weeks.
i simply want to know how long someone has to be gone to be able to say "yeah shes gone and not coming back.
more so, change the locks and stuff and and move somebody else (a family member) into the room.