Find Dupes across multiple wkshts and color the cell

Hi All,

I am a newbie and my first post--hoping to get some help.

I am tracking appointments and training qualifications by name (of person appointed) and date of qualification. Each type of appointment has its own worksheet, but each appointment may have some of the same training qualifications.

What I want is to highlight (color) the cell that contains the person's name if it is duplicated on another worksheet. I do not know how to do this across multiple worksheets.

I have attached the file for your convenience. I would appreciate any help. :)