In a word--no.While certainly early possession *could* be granted prior to closing--though it is strongly recommended against, since it puts risk on the seller; if the buyer wants the place early, find a way to move up the closing--that has to be done with the seller's agreement. It's not the realtor's house; he or she has no legal authority over it, unless the seller happened to grant the realtor the power to do this. But without such a grant, the realtor cannot give someone possession.You could sue the realtor for compensation if he let someone into your home without your permission, and you could also if necessary sue the buyer for compensation (effectively "rent") and/or to evict them and get them out. You need to balance what you want to receive vs. the impact on the sale in making your decision. You should consult with a real estate attorney.