It's possible to pause a Workflow from within a Booking at anytime:

When a Booking is archived, or the Booking Status is changed to Lost an optional pre-selected checkbox will appear when making either change.

The "Pause all workflow Tasks" is in relation to future Workflow Tasks that haven't yet been created. At the moment any pre-existing Tasks will remain.

If these previously created Tasks won't be required any longer, you can delete them (or mark them as complete).