Employee Scheduling using Excel

Hello,

I'm trying to create an excel sheet for employee scheduling. If I type the name of the person, is it possible to create a formula or conditional format to change the name red if it is already used in the same row (or even better, day before and day after)? That way, I know that employee is already used. I was thinking of making the same excel table on another sheet and using that for all formulas needed or referred to? Does that make sense?