Delete Personnel number

Hi,

I am trying to delete personnel no. of an employee. I am doing this thru PA30.

In PA30 For specific PERNR --> Utilities --> Del Personnel No.

I also tried to delete this personnel no. thru tcode - PU00.

on the next screen, I am not getting icon for deletion or any other icon for that sake and also in HR Master data menu on this screen, delete option is greyed.

Can some one tell me whats wrong...How can I delete this Personnel No.

I dont want to you prog RPUDELPN as this errors out in my environment.

Thanks,

Dhiraj