No need to have a separate fact table to store all those dates.
The ticket process is actually a perfect candidate for an accumulating fact table
If you are interested in a current status snapshot of tickets, then a standard accumulating snapshot is ideal. You add in some extra fields for each of those dates on the fact table (date dimension FK's), and fill them as the information becomes available.
If the detailed history of each ticket change is required (as Jeff mentioned, tickets regressing in their status) then a Time stamping accumulated snapshot
might be more appropriate, but this is overkill IMO.