Let's imagine we have presidential elections on 1st October 2018.
To facilitate voting we create work objects TODAY (1 work object = 1 vote). We don't want to create assignments "StartVoting" yet because it's to early so we establish wait shape in our flow that holds creating assignments until is 30 days before election day reached (create assignment "StartVoting" when date = election date - 30 days). So all work objects are created and wait shape's SLAs wait with creation of assignemnts.
Situation changes. Elections are put back 1 year earlier so election day is now on 1st October 2017.
We need to have our assignments created ASAP (only 26 days left). Let's say that we update election day without a problem but how to have our assignments created earlier? How to recalculate wait shape's date when assignments should be created?
This is a previously asked question in this forum. There is no Pega OOTB way to achieve this requirement. You have to implement the same in your application Pega has provided sample flowaction pyAdjustSLATimes to change the SLA. You have to fire some activity once the election date is changed to do the same task as done during pre and post processing of pyAdjustSLATimes flow action. Hope this helps!.