Change Compiled by: in Cisco Version

I onced worked for a guy who had somehow changed the name in the Compiled by: portion in a Cisco router Version information listing. For example, If I use a ‘show ver’, I get:
Cisco Internetwork Operating System Software
IOS ™ C3550 Software (C3550-I9Q3L2-M), Version 12.1(19)EA1, RELEASE SOFTWARE
(fc2)
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Thu 23-Oct-03 21:25 by yenanh

I’m curious if anyone knows how the “compiled … by yenanh” is changed, and if there are any legal implications in doing so?