SQL Duplicates

How to

Table is not indexed. Columns are fname,lname,mname,dob,facility,startdate,stopdate.

There are multiple records with same fname,lname,mname,dob and different facility also
records with only one fname,lname,mname,dob

question is:How to find fname,lname,mname,dob that have more than one record and different facility.
using standard SQL (Microsoft Transact SQL)