WorkFront has no ability to 'undo last action' - in some cases this can be very troublesome - as it is quite easy to make a change to basic project behaviour, critical path and end dates.
An 'Undo' last change function would be very useful if the Project owner has in-advertantly made a change that has caused multiple activities to be impacted.
Even a - revert to last saved version function might be useful - at least allowing the project owner to go back to a version that they have already reviewed and approved with their team.