It is often advised that far in the centre of the betting circle and seated near enough for the dealer to draw his notice is the best position to place your money to exchange for chips. Doing this when he is delivering the previous hand is also polite. In this manner, he will be aware that he must look after you after paying out bets and before dealing the next hand. In the same vein, can the dealer also exchange the chips for money after you have finished playing?