Yes, it is possible to switch to another hosting plan, however, it would require a server migration. If you wish to switch to another hosting plan either from Cloud web hosting to WordPress hosting, Reseller hosting or managed cloud server then you need to contact support for assistance.
Upgrading between two different hosting packages can only be done manually and involves migrating your website content from your current hosting package to the new hosting package. You need to contact support and provide us with the required details like the service you wish to upgrade, to and the plan you are upgrading from and to. Once support has the required information, the migration process starts.
Once the migration is complete, you will be contacted to modify your DNS records to access your migrated site (on the destination server).
Please do NOT cancel your current hosting plan until the migration is completed.