Every character on Jiǎoluò Shūwū read as huan in any tone — 2 readings total across the four tones. Pick the tone you mean.
If you have the sound huan but not the character, here are the 2 characters read this way: 欢 (huān, joy, merry, to be pleased), 换 (huàn, to change, to exchange, to swap, to trade). They split across 2 tones, so the tone is what separates them.