Changing master account code on one of the slave extensions through MySQL:
use pbxware_300;
update users set value='112' where name='account_code' and ext='117';
update admin_site.300_pbxware set data = REPLACE (data, 'slave_accountcode=>100', 'slave_accountcode=>112') where ext='117' and ref='sip:ext';
The first command will set Master Account Code to 112 in backend for extension 117
The second command will make it visible in GUI:
'slave_accountcode=>100', --- old master account code on extension 117
'slave_accountcode=>112', ---- new master account code on extension 117