Need Help!!!!

Hi everyone.

I am having some issues bringing a date into a card into BI.

Basically, I have a date column which gets updated randomly (around once a week) I have a column with the latest date in as that is simple (lastdate function) However, I want last but one date in the column and every measure i have tried, it comes up with the day before the last date when there is no data in there for that date.

Example: - Last date is currently 13/08/2018. Previous date before that is currently 10/08/2018. How do I bring in this date. I thought it would be like lastdate - last date -1 or previous day function but nothing works.

Can someone help please..

Thank you