Interesting question and one I think with an easy answer. Just create a new relationship directly down from the Client to the Properties, and the Properties will directly "know" if the Client Cancels.
if you did not rename your fields, you would have a Relationship between Clients and Debtors connected by the reference field [Related Client]. Just bring that Related Client field down one more level to the Properties table and then create a new relationship between the Clients and the Properties. Once you do that, add a lookup field to indicate if the Client has cancelled. This new relationship will "connect" automatically - there will be no manual entry required to make that connection.
Mark
