You may check which stored procedures gets executed when you're querying the charname overview(I guess) by using an SQL Profiler... OR use the Database.. ^^
Code:
USE SRO_VT_SHARD
exec _RenameCharName 'Curname','Newname'
This procedure does hopefully the job, if your database doesn't have further tables with your charname you're probably good to go - otherwise revise the sp or write your own one.
AND don't ever edit your charname manually on the _Char table, it may end up having problems ingame since the charname is used in various other tables as well (e.g. _GuildMember, _Memo).
