Yes, the administration interface can change the number of processors, memory, or storage space? The upward change will cause additional costs, and the downward one will reduce costs.
The cost change will be made from the moment the VPS server size is changed.
Changing the hard disk (storage space) involves certain conditioning of the number of processors and memory. That is why a downgrade can later be more difficult to perform automatically. For storage, we recommend an additional volume connected to the server. This volume can then be linked to another server.