Go to 'My Properties' - 'Edit Properties' and simply click on 'Delete' along side the property you wish to remove.
Please bear in mind that this will disconnect the property from the channels that you are connected to. However it will not delete the property in the sales channel. In order to delete the property in the sales channel, you need to contact the channel to request it. You can find the contact information for each channel under 'Channels' - 'Channel Info'