A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Dear Chuck,
Excel treats dates as Number while formatting is only for visual display to us.
What you are encountering is due to change in format of the cell to Date specific function.
Please try below formula. I hope it works out for you.
=IF(B2="","",A2&": "&TEXT(B2,"dddd")&", "&TEXT(B2,"mmm")&" "&DAY(B2)&", "&(YEAR(B2)))
Additionally it will be safe to use the formula given above as it will make outcome independent of format of source cell :):):)