R.B.
She could be waking over molar teething? I'd just give her a dose of Motrin, and comfort her for a minute, but tell her she has to sleep in her own bed.
Even if its not teething, but just dreams, or light sleeping -- it's important for children to learn how to put themselves back to sleep. And 2 is so age appropriate for when this "relearning" sleep patterns happens.
It's hard, but trust me -- it takes 2 nights to make a habit -- 2 weeks to break one!!!