CONVERT DECIMAL TO DATE in DB2 sql

I am trying to write a sql to convert Decimal to Date in DB2 but below error is thrown. "Error: [SQL0204] TO_DATE in *LIBL type *N not found"

Please assist me on this issue.

MYDATE Decimal(7,0)

select To_date(MYDATE, 'DD-MON-YYYY') from MYTABLE