In FTP client:
rename /public_html/upload/64/SomeMusic.mp3 /public_html/archive/2011/05/64/SomeMusic.mp3
With FTP commands:
RNFR /public_html/upload/64/SomeMusic.mp3
RNTO /public_html/archive/2011/05/64/SomeMusic.mp3
source:
http://www.nsftools.com/tips/RawFTP.htm