In the HubEngine, you have the option of deactivating connections individually within a plan. This only makes sense for a bidirectional plan. You can deactivate a unidirectional plan by clicking the general deactivate button in the upper right corner.
Sometimes you want to deactivate a connection of a bidirectional plan afterwards, e.g. because you only used it for testing. Navigate to the respective connection tab of the plan. Under Advanced Options you can activate a checkbox (see screenshot).
After you have saved and opened the connection again, you will get the following warning that the connection is deactivated.