Need to delete birth name and date of birth - they relate to another person with the same name

There are two entries John Pett (I) nm0678489 and John Pett (II) nm11013870. As far as I can tell, they are different people. I have moved director, producer and writer credits from JP(I) to JP(II), leaving sound credits which I think do relate to JP(I).

I need help to delete JP(I)'s real name and date of birth which relate to JP(II) and exist for him. I can't delete them using the update form because it needs URLs as evidence, which is a bit difficult when you need a URL to support information *not* applying to a person ;-)