CC checks the cloud database every time you connect to the cloud provider. If the calibre database in the cloud has changed since the last connect, CC will automatically download that updated copy.
If in CC you are connected to a cloud provider and want CC to download an updated calibre database, do one of:
- disconnect and reconnect from the cloud
- use the "Change cloud library" feature (in CC's menu when connected to the cloud). If you choose the library you currently have open, CC will verify that it has the latest database.