Ranch Names can be changed if you buy a sponsor from another player using an Op as a MiddleMan, if the ranch name is inapporpriate, or if it contrains the name of a breed you no longer work with. You have to link your account to OrbisWorlds and put a support ticket through. If its approved, an Op will contact you and the name can be changed.
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Here's the link to the thread containing all the information you need.
http://virtualhorseranch.com/phpbb2/vie ... p?t=105509