Can you elaborate a little more so people here can help? Just saying Replace Face does not work is not giving us too much to work with. Maybe you can attach your file and tell us what face you are trying to replace and with what part need to be the replacement surface.
@Thank You very much for your quick response,
I am trying to replace the wavy surface part to the round part same like solid work replace face sample.
I saw on the you tube it was very simple, but I can not make it.
Make sure that the replacement face is larger that the face you are replacing.
Replace face usually works best when you replace one face for one surface face. Sometimes it works for replacing two or more faces but rarely. It is one of the most important tools in m SW arsenal and you will see tons of replace faces in my models. BTW, the replacement face DOES NOT have to be larger than the face you are replacing; that is the beauty of this tool in that it automatically extends the tool face's boundaries when doing a replace. If you need some help show is what you are trying to do.