As mentioned above, there can be three important calibration tables in a visibility dataset - the gains, leakage and bandpass items. Although there are subsidiary items associated with each, these are the main items, and by deleting any one of these you effectively prevent the calibration operations associated with that table being attempted.
The task to delete items is delhd. For example, to delete the gains item of the dataset multi.uv, use
|in=multi.uv/gains||Delete the gains item of|