Running training plan - change the final date

Hi all,
I have registered for the 13.1 training plan over 16 weeks.
I messed up with the dates and got registered too late (by a week) to finish all the sessions by race day.

I’d like to skip the first week in order to align race day with the rest of the training. But I have no clue on how to do this, nor did I find the information anywhere in the forum.
There is this sliding bar that is supposed to adjust the end date when you enroll, but it does not change anything to the final date.

Has anybody faced the same issue and found a work around for this?

Thanks a lot.