If you do not renew your Hosting but keep your Domains still registered with us, you can continue to manage and renew your Domains directly through your Account Manager — where you can also update and manage the nameservers of your Domain and change its contacts.
You may reserve a Domain without having a Hosting service for it through Domain Name Parking. Anyone who will access your Domain will see a placeholder website instead. This is a good way to reserve a site that you want to create later if you don't have money yet for the Hosting plan that you need. It's a trick that a lot of webmasters use if they have an idea for a new website but don't want to commit to creating it at such an early date.