Twice a year there is a time change, once in the fall and once in winter time. Usually your smartphones have the preset that the time changeover is automatic. However, it may also happen that this automatic time adjustment does not work correctly with your Samsung Galaxy S6.
If so, then you must check the following settings please:
1. Open on the Samsung Galaxy S6 the Menu --> Settings
2. Search here for "Date & Time" and tap on the entry
3. Ensure that the following two entries are enabled:
- Automatic Date and Time
- Automatic Time Zone
If you have activated these settings, then the Samsung Galaxy S6 should from now on perform the automatic time switch from summer to winter time and vice versa. You know now how to activate the automatic time change in Android on your Samsung Galaxy S6.