While the suggestions here are mostly valid, what everyone seems to be missing is that the request is to be able to store a date into a PPM field. For those that aren't familiar with, or have just forgotten, all PPM parameter fields are VARCHAR types, so the TO_DATE function should NEVER be the outer most function in a select statement that will be fed into ksc_store. It must be in a character format, and more specifically, PPM stores date values in the database with this format string: 'YYYY-MM-DD HH24:MI:SS'. If it's not in that format, PPM will not allow it to be stored into a date field as it would violate the validation of the field.
I've done many such date manipulations in the 12.5 years I've worked with PPM/ITG/Kintana. Here is what I would do: