Here in London, we are currently 1 hour ahead of UTC. So – if I take your timezone without timestamp and say it is in UTC I will get it printed for my local timezone.
richardh=> SELECT ((timestamp '2015-10-24 16:38:46') AT TIME ZONE 'UTC');
timezone
------------------------
2015-10-24 17:38:46+01
(1 row)
But you want “EST” which seems to be somewhere in the Americas, judging by the value returned. You can wrap the expression in a little SQL function if you wanted to.
richardh=> SELECT ((timestamp '2015-10-24 16:38:46') AT TIME ZONE 'UTC') AT TIME ZONE 'EST';
timezone
---------------------
2015-10-24 11:38:46
(1 row)
Edit: how to do it in a query
SELECT ((stored_timestamp AT TIME ZONE 'UTC') AT TIME ZONE 'EST') AS local_timestamp
FROM my_table;