to use

用 has also the meaning of "to need": when someone says 谢谢 (xiè xie; thanks) to you, you can kindly reply 不用谢 (bú yòng xiè; "no need thanks" = "you are welcome"). Another common way of saying "you are welcome" is 不客气 (bú kè qì; "no polite"). by XiaoAn