READ and WRITE form: little issue with empty fields

hello wix forum,

as a newbie I finally managed to create a form which is connected with a dropdown-menu to a database.

so on top of the form i select a name see their specific datas (time picker, time)

MY PROBLEM now is:
if i change the name in the dropdown-list and choose another NAME it shows the right data(=time) AS LONG the field is NOT EMPTY…
then my form keeps the “old” data.
so it only “refreshes” if the data-value changes.

could you ladies and gents give me a little hint how to solve it?
IF a code is needed please provide where to put this code since I´m really new to this media and willing to learn ;-))

GREETS from VIENNA/AUSTRIA
THOMAS