In the Status field, change the status cancelled. In the majority of cases, this will be 'C', if you are unsure, search in the status field for the list of options.
All the contract lines will turn pink and the goods value reduced to zero. This will happen only if the contract lines had the 'Auto Line' box ticked i.e. the line follows the status of the contract.
If you change the contract status to 'C' and a line is not cancelled (did not turn pink), double click on the contract line number to go into the Contract Line Details and check that the Manual Line box is unticked and the Auto Line is ticked.
You can now add the item for a cancellation charge (see Creating a New Contract for a Conference) if this is required. If a cancellation schedule has been set up in the Conference Set Up, and the Cancellation Terms Apply box ticked in the Contract Line Details when the item was added, the cancellation fee will be calculated automatically by the system, a box will inform you of the cancellation fee to be charged to accept or decline.
Unticking the Active Line box in all the contract lines on the contract will take it out of any further processing, e.g. if you did not want a credit note produced if the line had been invoiced and then cancelled.