Merging similar names.

[avifatal]

Hi,
When I use the following sentence, the output will be

text = ("My name is Robert Clinton, but you may call me Robert")
ents = nlp(text).ents

The output will be: [('PERSON', 'Robert Clinton'), ('PERSON', 'Robert')]

But when I use

text = ("My name is Bill Clinton, but you may call me Bill")
ents = nlp(text).ents

The output will be: [('PERSON', 'Bill Clinton')]

1. What is the difference between Robert and Bill?
2. In general, how may I merge down similar extracted items (persons, orgs and such).
3. Regardless of the first 2 questions, how can [('PERSON', 'Robert Clinton'), ('PERSON', 'Robert')] may be merge to [('PERSON', 'Robert Clinton')].

Thanks