For VPS:
Navigate to the Dashboard for your VPS. Then click on More > Upgrade:

On the next page at the bottom, you have the option to upgrade or downgrade your VPS to the desired level.
Press Continue to complete the order

Important Information About Downgrading VPS
When you downgrade your VPS from, for example, VPS MED > VPS SM, the amount of storage never decreases. This is because it is technically impossible to reduce the amount of storage without corrupting your data.
The end result is simply a VPS SM with extra block storage!
The amount of bandwidth you had on the previous plan can also remain, but you can easily downgrade it freely to get an even lower price!
For web hosting
In the overview of your service, click on “Upgrade/downgrade” as shown in the image below:

Choose which level you want to move to and press Continue to complete the process!
