Unique List From Row Name Based On Criteria from Column Data Header and Column Contents

Hello,

Hoping someone can help. I need to create a unique list of employees who will be working on specific dates. What I have is the list of employees in A2:A15, the list of dates in B1:N1. When the employee is scheduled to work that day, an "X" is placed in the cell corresponding with their name and the date.

I need a formula that can be input into B20 and then copied down and over, that will generate the unique list of names that have an "X" next to their name in the given date in row 19. For example, B20 and down should read:

Aaron Dotson
Darris Lee
Charles Matthews
Jason Harris
Alexander Sinegal
Daniel Sepulveda

I don't mean to be redundant, but basically, I just need a dynamic formula that will look at the date above itself in row 19, find that date in B1:N1, find where there's an "X" in that column, then return the name associated with it in A2:A15. I want it to create a unique list so that I can just copy the formula down and won't need to update the formula as employees come and go. Something like an INDEX MATCH INDEX COUNTIF. I don't want to use a pivot table or any VBA coding.. I've been trying to crack this thing all night but my brain is cooked.