how to delete members without banning them?

[albano]

For those that need to do it via SQL query

UPDATE `mybb_posts` SET `username`= "<newusername>",  WHERE `username`= "<oldusername>" 
UPDATE `mybb_threads` SET `username`= "<newusername>",  `lastposter` = "<newusername>"  WHERE `username`= "<oldusername>", `lastposter` = "<oldusername>" 

You really need to test this first in a non-production forum before rolling it into production.