diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
new file mode 100644
index bb794e0..5e3d54f
*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
*************** SELECT date_trunc('year', TIMESTAMP '200
*** 8082,8091 ****
! The AT TIME ZONE construct allows conversions
! of time stamps to different time zones. shows its
! variants.
--- 8082,8092 ----
! The AT TIME ZONE converts time
! stamp without time zone to/from
! time stamp with time zone, and
! time values to different time zones. shows its variants.
*************** SELECT TIMESTAMP '2001-02-16 20:38:40' A
*** 8145,8153 ****
SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'MST';
Result: 2001-02-16 18:38:40
! The first example takes a time stamp without time zone and interprets it as MST time
! (UTC-7), which is then converted to PST (UTC-8) for display. The second example takes
! a time stamp specified in EST (UTC-5) and converts it to local time in MST (UTC-7).
--- 8146,8158 ----
SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'MST';
Result: 2001-02-16 18:38:40
! The first example adds a time zone to a value that lacks it.
! The second example shifts the time stamp with time zone value
! to the specified time zone, and returns the value without a
! time zone. This allows storage and display of values different
! from the current TimeZone value. Converting
! time values to other time zones uses the currently
! active time zone rules since no date is present.