The data in your Excel file need a bit of preprocessing, then the conversion is straightforward:
D = readtable('Date-Time.xlsx','ReadVariableNames',0);
D.Var1 = datetime(strrep(D.Var1, '''', ''), 'TimeZone','Europe/Athens');
then to do the conversion:
Original = D.Var1(1:5,:) % Information Only (Delete)
D.Var1.TimeZone = 'UTC';
New = D.Var1(1:5,:) % Information Only (Delete)
producing:
Original =
5×1 datetime array
31-Dec-2014 23:00:00
31-Dec-2014 23:00:00
31-Dec-2014 23:00:00
31-Dec-2014 23:00:00
31-Dec-2014 23:00:00
New =
5×1 datetime array
31-Dec-2014 21:00:00
31-Dec-2014 21:00:00
31-Dec-2014 21:00:00
31-Dec-2014 21:00:00
31-Dec-2014 21:00:00
