It's the latest euphemism for "communicating with a person in some manner whose details are not relevant" to join the already well-populated set { "approach", "contact", "consult", "get in touch", "speak with" }. I hate "reach out" with a passion and draw instant conclusions about those who use it, but I'm sure that most of the above were also hated when they were invented and it does fill a need for a missing verb in English.