In Binance and Kucoin you deposit your USDT there and there is an option to convert it to other currencies without commission and you withdraw it
Problem solved
What I know is that he is probably trying to avoid withdrawal fees for that amount he is trying to exchange. I believe he wants the assets in an external address and not his exchange account.Problem solved
For example, in Binance, withdrawal fee for;
1. BTC - 0.0002 (~$14)
2. ETH - 0.003 (~$12)