how do you tell someone at work who you dont really know that their fly is open? Its kind of awkward when they are standing there talking to you.
Re: how do you tell someone…
well don’t laugh out loud in her/his face 
try to whisper in their ear slowly and quietly so they don’t get too embarrassed and you save them from a whole day of laughs at their expense
Re: how do you tell someone…
i see london i see france, i see coworker’s name’s underpants.