#cosleeping

How do I get my child back to sleeping in her bed after multiple disruptions in routine?

We have talked about going back to their own beds like before and one of my daughters says she will do it but the other says she is not ready. My daughter, who said she will do it, doesn't want to sleep alone (without me or her sister) so we end up all sleeping together. How do I get my daughter who said she was not ready to go back to falling asleep in her own bed? I have never been strict about them coming into bed with us but just wondering how to go about getting her back into the old routine......thank you!!