#cp /usr/share/zoneinfo/America/Vancouver /etc/localtime
or
#ln -sf /usr/share/zoneinfo/
America/Vancouver /etc/localtime
One more point you need to add in post is:
if copy or create symlink but zone change not reflecting than
#yum search tzdata
#yum update tzdata
than execute date command.
you get the correct time zone.
REFERENCES
