Much like how The Cloud allows us to access information remotely from our phones, work computers, and personal laptops, Bernard could be using different devices (Dolores hosts) to access her subconscious during their private conversations. This would give Bernard the ability to communicate with Dolores without actually removing or interacting with the host himself. It would also give him an easy out, by making Dolores believe that her conversations with him are all part of her dreams.

This theory would clear up a few reoccurring questions from the scenes where Dolores is in an isolated area with Bernard. It would explain why no one has ever mentioned Dolores' absence from the park. It would also explain why she is always wearing the same blue dress when they talk, instead of her white nightgown or nothing at all.

Going off of this theory, who's to say that there aren't more Teddys, Maeves, or Armistices waiting in cold storage to be sent into the park? The possibilities in Westworld are endless.