DreamHost does not offer any service that temporarily suspends an account without the risk of losing data. You must instead close the account.
If you must suspend your services for any reason, DreamHost recommends that you close your account through the DreamHost panel. You can add services at a later date to re-establish hosting.
If you ever wish to come back, you can follow this method to re-enable your account.
Always make a Backup of your account before closing it, as DreamHost cannot guarantee that any of your data will be saved.