Need to change date time with only date

If you would like to display date in specific format, please read this:
Standard Date and Time Format Strings | Microsoft Docs[^]
Custom Numeric Format Strings | Microsoft Docs[^]

So, DateTime.ToString()[^] should do the job:

Dim stringdate = "19/05/18 06:20:40"
Dim provider As Globalization.CultureInfo = Globalization.CultureInfo.InvariantCulture
Dim mydate = DateTime.ParseExact(stringdate, "dd/MM/yy HH:mm:ss", provider)
Dim formatdate = mydate.Tostring("dd/MM/yy")
'prints 19-05-18 in Poland
'prints 19.05.18 in Germany
'prints 19/05/18 in USA

As you can see a date format depends on system settings. In case when a date separator is different then "/", then you have to use DateTime.ToString Method (String, IFormatProvider) (System)[^]

Dim formatdate1 = mydate.Tostring("dd/MM/yy", New Globalization.CultureInfo("en-US"))