To Upgrade and Downgrade resources (CPU, RAM and Storage) in VM need to follow some steps.
1. Login to your vCloud Director
2. Choose VM need to change.
3. Right-click and select Properties.
4. Go to Hardware tab. You will see VM resources configuration.
5. Assign CPU, RAM or Storage capacity you need to upgrade or downgrade.
6. Save configuration.
Please note that you should restart VM if needed.