taking time off an existing date time - that changes the date

[Kearnd967]

Good afternoon.

I have a problem converting a date time into a different time zone.

My input is correctly formatted as a date/time yyyy-MM-dd HH:mm:ss

I use the formula 

if [Time Zone] = "DST" then DateTimeAdd([Off Merge],-60,"Minutes") else [Off Merge] endif

This effectively takes 60 minutes off each of the times where the Time Zone is listed as DST.

However, if the time is less than 01:00:00, the formula fails and nothing is changed.  I would want the time and date to change, for example:

2023-10-30 00:30:00 should become 2023-10-29 23:30:00

Any ideas why this would not be happening?

Many thanks in advance.

David.

[binu_acs]

@Kearnd967 I can see the change in time