I am using this query on Informix side.
select first 10 acd,seq_num,
EXTEND(DATETIME (dbinfo('utc_to_datetime',seq_num))YEAR TO DAY, YEAR TO HOUR) + INTERVAL (4) HOUR TO HOUR
from haglog;

I want to add 4 hours to the utc time value that is obtained after using dbinfo function. or how can I simply convert my column seq_num that has local unix time into datetime?