Workouts in training plans

When I am working my way through a training plan - the specific workouts are expiring on a very tight programme.
IS there a way to do a workout that has expired?
Some of the plans have 6 workouts per week , so in the real world (you know the one with real families, and the one where we earn money to pay our Zwift subscriptions…)
you can’t always stick to the arbitrary rules and want a bit more flex in the schedule.
In the 6 week and 12 week FTP this isn’t an issue as they are in the workout section… but in for example TT tune up AFAIK there is not a get-around?
Or put another way, Ive paid for that session so its up to me not you when I do it…