During a session, an upgrade can be performed in a similar manner as the placement of a building. The only difference is that, rather than empty terrain being valid, a building with a valid type of function must be valid.
- Find a building with a function fit for upgrade.
- Select the upgrade to perform.
- Draw the selection for the upgrade.
- Press the "Upgrade" button.
- If required, use the popups to request and acquire a permit.
- The upgrade has now been performed.
