The Failover action lets you specify specify destinations by priority, Print Distributor will try the first action in the list, if that isn’t available then it tries the next and so on until it succeeds.
A typical scenario might be if you have two printers, one large printer for the bulk of your work and a second fall back printer for when the main printer isn’t available. You can add both of these printers in the Failover action, Print Distributor will send all the documents to the first printer by default. If the first printer is offline for some reason then Print Distributor will ignore it and use the second printer.
You can also use the Failover if you are writing a file, maybe the first write file action writes to another network server, if that fails then you can write the file locally instead.
You can also mix action types, for example the final action might be to log an error message.
The only property on a Failover is the title, it is configured by adding child actions in the correct order.