You can send a booking cancellation email to a supplier in the same way you send a booking request (select the item > Send booking > Cancellation request).
The supplier can respond confirming the cancellation and whether or not there is a fee.
The items booking status should update automatically throughout the process.
Cancellation Requested: cancellation request sent. The price remains locked.
Cancellation Confirmed: cancellation accepted/confirmed. No supplier payment is created.
Cancellation Confirmed with fees: cancellation accepted/confirmed with a fee. A supplier payment will remain visible in the Payments tab.
You can manually change a booking status by selecting the item and clicking 'change status'. You can also change the status on the edit booking page which you can find by selecting the options icon (three dots).
If you want to remove the item from the itinerary, you will need to select a non-booking-cycle status (e.g. not yet requested) before deleting it from the Build tab.