Virtual Sales Agents and Live Sales Agents

This post really refers to two different ideas. But maybe not as you might initially expect.

Most of us are familiar with the virtual agent software packages that exist. Many are poorly instructed and can handle only 2 or 3 keywords, largely due to laziness of the person setting them up or limitations of poor programming.

At the other end of the spectrum is the actual live person sales agent. Someone who can answer questions, find out information, and genuinely communicate with the customer.

Does anyone know of an implementation method that would allow a "virtual sales agent" to be offered (or to offer its help) when no live agent is available, and allow a method for leaving a message for contact by a live person when one becomes available. But if a live person is signed in right now, that the virtual sales agent wouldn't get involved, but instead the live person would be the one they would reach?

While I understand that not every question can be fed into a virtual sales agent program, having access to a live person who can actually log the questions and concerns of a visitor/prospect as well as answer and research questions, would provide a large resource for determining what information the virtual agent might actually need to have added to it for when a live person is not online.