Converting date to day of week error- blank cell autopopulates

Gah! I've been researching this issue for three hours now and need some help.

I found the formula to convert a date mm/dd/yyyy into the day of the week:

=CHOOSE(WEEKDAY(A2),"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday")


Works like a charm for the cells in column A that are populated.

Problem is, the cells in column A that are empty are all showing up as "Saturday". I need those cells to be blank so that when my staff enters the date of service THEN the day of the week pops up in column B (formatted with the above formula).

What am I missing here?

It worked! I thought I might need to add an IF function but could not figure out where. Thanks so much for the quick response. You're the best!