Alter the letters after "ACCOUNTS\" to lower case? I have a database table, users, with different username cases (see the example). How can I update the letters after ACCOUNTS\ to lower case?

ACCOUNTS\James.McAvoy
ACCOUNTS\michael.fassbender
ACCOUNTS\nicholas.hoult
ACCOUNTS\Oscar.Isaac


Desired result after the update:

ACCOUNTS\james.mcavoy
ACCOUNTS\michael.fassbender
ACCOUNTS\nicholas.hoult
ACCOUNTS\oscar.isaac
UPDATE dbo.[User]
SET username_column = N'ACCOUNTS' + LOWER(SUBSTRING(username_column, 9, 4000))
WHERE username_column LIKE 'ACCOUNTS\%';