Depends what version you're using, on mine it's ost_ticket_priority, you'd want to change the field priority_desc for id 4, ie:
UPDATE `ost_ticket_priority` SET priority_desc='Critical' WHERE id=4;
However, the prefix is likely not the same, so match that to whatever your database is set to.
If they've changed it again, you can check your version of class.forms.php eg: https://github.com/osTicket/osTicket/blob/develop/include/class.forms.php#L2240
That will change it for future ones, to update all previous tickets text (because, it's a form, so the value is stored in the values table..) You'll want to find the id of your ticket form status field.. on mine it's 22, but really look for it, don't just run random sql.. To do that on mine it's Admin -> Manage -> Forms -> Ticket Details -> "Priority Level" -> Config button.. hover over it and the url will show you the field id like ...field-config/22
So, to update mine, it would be:
UPDATE `ost_form_entry_value` SET value='Critical' WHERE field_id=22 AND value_id=4;
Then, all past/future emergency priority text strings will be updated to "Critical".
