English to Greek Law/Patents Law: Contract(s)

Hello,

I have to translate the "Executor Dative" to Greek. I have found out that There are two types of executor. There is an executor nominate, and an executor dative.
An executor nominate administers the estate of a deceased who left a valid will.
An executive dative administers the estate of a deceased who did not leave a valid will. The deceased is said to have died intestate.
In practice both types are called executor or executors.
I have thought of leaving it just "Εκτελεστή" but I would appreciate more suggestions.

Thank you!