chat – ChatBox UX: how to manage large datasets? (for example, search for a user)

I'm considering a bot to automate some of my administrative tasks.
For that, I would like to be able to say something like "delete user John Doe".

But John Doe is not unique. I would need the unique user name of John Doe to be properly identified because in my system I have several Johns and several does.

Now, how can I help the administrator to correctly identify the desired user? Typeahead (is this an option for discussion robots?) Additional clarification questions? How to treat partially correct data?

Examples on how other chatbots deal with these scenarios? Or mitigate?

Any thought would be welcome.