Question: how to change date format in oracle with timestamp?
Answer: Formatting of the new TIMESTAMP datatype is the same as formatting the DATE datatype. ... 
Formatting of the TIMESTAMP datatype:
SELECT TO_CHAR(time1,'MM/DD/YYYY HH24:MI:SS') "Date" ... 
Formatting of the TIMESTAMP datatype with fractional seconds:
SELECT TO_CHAR(time1,'MM/DD/YYYY HH24:MI:SS:FF3') "Date"