I would like to change the date 5/8/2020 to YYYY-MM-DD format i.e 2020-08-05 What function I need to use for that?

but this is working .  Result : 8/5/2020

SELECT TO_DATE('5/8/2020','DD/MM/YYYY')

When I use TO_DATE function I am getting error. Please see below

>[Error] Script lines: 1-1 --------------------------
 [SQLCODE: <-400>:<Fatal error occurred>]
[Cache Error: <<ILLEGAL VALUE>todate+32^%qarfunc>]
[Location: <ServerLoop - Query Open()>]
[%msg: <Unexpected error occurred:  <ILLEGAL VALUE>todate+32^%qarfunc>]

SELECT TO_DATE('5/8/2020','YYYY-MM-DD')