# Replace an unsupported ALTER USER setting change

Coordinator DB does not support `ALTER USER` for settings profiles or credential changes. Credentials and SQL request defaults use different interfaces. Select the one that matches the intended change instead of rewriting the same unsupported statement.

## Change credentials

Users are declared in the file selected by `users_config`. A user has exactly one password representation and can have an HTTP API-key digest. Edit the existing file and restart the server to apply credential changes. Usernames are case-sensitive; duplicate users and shared API-key digests are rejected.

## Change a database default

Select the intended database and use a supported `SET` name, for example:

```sql
SET max_execution_time = 5;
```

The value persists for the selected database and affects later requests from other clients. It is not a private preference of the authenticated user. The change requires autocommit and no active transactions in that database, and it cannot relax a stricter server ceiling.

Use `system.settings` to inspect the effective result. Format options use statement `SETTINGS` instead of persisted `SET`. Record the actual error text when a change fails; an unsupported name, invalid value and active transaction require different corrections.

See [users_config](https://coordinatordb.com/docs/reference/settings/server-settings/settings/users), [SET](https://coordinatordb.com/docs/reference/statements/set) and [format settings](https://coordinatordb.com/docs/reference/settings/formats).