code: func (ftp *FTP) Rename(from string, to string) (err error) {
  	if _, err = ftp.cmd(StatusActionPending, "RNFR %s", from); err != nil {
  		return
  	}
  
  	if _, err = ftp.cmd(StatusActionOK, "RNTO %s", to); err != nil {
  		return
  	}
  
  	return
  }
docs: // Rename file on the remote host