Resolved String Manipulation

[ameanberg]

I kept on wondering what I was doing wrong with the string manipulation commands and I thought I made a stupid mistake or something, but after this test. I think I'm just lost with this...

fromemailaddress = "123"
fromemailaddress.Replace("123", "d")
Debug.Write(fromemailaddress)
Output:123

I'm sure I made a stupid mistake. Please point it out to me promptly XD.
Edit:So it turns out its a function and not a command.