convert cell timezone

Hello, I have a column with date/utc time like: 2015-02-23 08:22:35

I would like to make another column that converts this to usa est time and another that converts it to usa pst time.

I have installed the “jave time zones” extension and can not figure out how to use it.

Can the conversion be done using a formula?

What would that formula be?

Thank you,

Unfortunately I am not familiar with the extension, but personally I would use something like this:

=A1-TIME(5;0;0)

for a UTC-5 time zone.

I’ve used this and in excel it works fine but in Libreoffice 7.1 I get a #Value! error. Any ideas?