There are three ways to convert Oracle timestamp type is date.
1, to_char first into character, using to_date then converted to date type
select to_date(to_char(systimestamp,'yyyy/mm/dd hh24:mi:ss'),'yyyy/mm/dd hh24:mi:ss') from dual;
2, using implicit conversion SYSTIMESTAMP + 0
select systimestamp + 0 from dual; --oracle automatically implicit conversion
3, using the cast function to convert
select cast(systimestamp as date) from dual;