EDIT - Tony adds this interpretation, which hopefully the OP will accept by removing this line.
If one of my pawns captures a Rook (which is on the 8th rank) can I promote that pawn to a Queen in the same move? In other words, can I capture-and-promote? What if I already have a queen? What if I capture a Knight, instead of a Rook? Can I do it then?
Edit: The question has been clarified. I interpreted the original question to be "can a pawn promoted to a queen be represented using a rook piece?"
One explanation for this is that your opponent may have a Queen already and wants to promote to have 2 Queens. One way to represent this is to take a Rook and place it upside down to represent the second Queen.
You are not limited to which piece you can promote to based on what pieces are off the board, as long as both players understand what it represents.
