Delete duplicate records by column 1 but having differ values in column 2 and column 3

I have a table like:

SSN FName   LName
1   a   b
1   a   b
1   b   b -------------> to delete
2   c   d
2   c   d

as above example I want to delete such records where SSN has different values in FName and LName columns.

Kindly help.