Copy a date while editing item

Hi!

*edit* People don't work 7 days, so some days will be empty. I'm thinkin' of a "IF" formula?

Is there a formula, that can copy the date that is in the previous column while the item is edited?

F.E.: Employees must fill in the starting date and time, and the end date and time (sometimes the work exceed the 00:00 time), but most of the work is done on the same day. So, it would be very handy to copy the date field (not the time!) in the next column, while keeping the Date/Time format

Monday Start     16-11-2020            08:00

Monday End     *copy date here*     16:00

Thank you so much, in advance.

Regards

Roel