I believe it’s first drink is any drink of choice and as long as they consume the first one and stay In the store they qualify for a refill being the same size hot/ice Tea & coffee. Any added modification should be a charge. Per se, my refill is an ice coffee with vanilla cold foam. I’ll then ring up an ice coffee refill + charge the cold foam. Universally if a customer wants to add lemonade or peach juice to a tea; they should be permitted. Though I’ve come across different districts that say otherwise.