copy text of other cell if there's a text in another

Hello:

I have two sheets in excel. 

I want to copy the text of sheet one in sheet two if there's a text in one of the colums in sheet 2.

So if in cell U3 in sheet 2 I have an "X", I want that the name in A3 in sheet 1 been copied in cell A3 in sheet 2.

Amazing thing will be if possible to eliminate automatically the cells in sheet 2 that doesn't follow the rule, so all the ones in wich there's text, came one by another. Imposible uh?

Hope my question to be clear, sorry.

Kindest regards