From MSNPiki

REA

MSNP11 (and up?): This command was dropped and replaced by PRP.

The REA command is used to change your displayed name to something else.

REA trid your_email newname\r\n

• trid : Transaction ID
• your_email : The email you use to sign on to MSN.
• newname : The name that you now wish to use in a URL Encoded format.

If the rename has been successful, the server will respond with the following.

REA trid number your_email newname\r\n

• trid : Transaction ID
• number : Purpose currently unknown.
• your_email : The email you use to sign on to MSN.
• newname : The name that you wished to use in plain text.