Changing End Dates of all Tasks based on a formula

Hello, is it possible to change end dates for all the tasks based on a formula.

For example, I have created a development plan and now I need to change the ending dates for all the tasks (hence the durations) according to the formula below:

New end date = (old end date) - ((task duration)*0.3)

No such feature, sorry.

Thanks Dmitry. That would be a great feature. To be able to shift an entire project plan.
I think it is possible to take the code, change it and build it. Right? https://docs.ganttproject.biz/development/build/