Suppose that in A2 cell you have a date/time value. The time details do not allow to use the date for calculations. You need to transform it to date only. The following two ways are described:

1. Select a blank cell where you will place the date value, and enter the following formula:

=YEAR(A2) & "/" & MONTH(A2) & "/" & DAY(A2)

2. Use the following function in the blank cell:

=DATEVALUE(A2)

This function transform the date to a number. Then, in the type of data use date and you get back the type of date you want.