The first step is to delete the data that has currently been synced into myday so we can have a fresh start. Please follow the guide on this link - How to complete a full re-sync of SQL table
After has been removed, you can now proceed to the steps below.
From the myday control panel, go to the data sync section in the myday control panel.
Click on details for the sync-eu.mydaycloud.com server.
On the next screen, select edit for the timetable and just set the timezone to London.
You’re now ready to start the sync process with the updated timezone.