incorrect date conversion

hi all,

i am trying to convert a string to a date, please help me on this.

i tried these options:

to_date('01/05/2015 10:00 PM','mm/dd/yyyy hh12:mi ') -> blank output

to_date('01/05/2015 10:00 PM','mm/dd/yyyy hh:mi ') -> wrong output  [output is 2015.01.05 10:00, but expected was 2015.01.05 22:00]

to_date('01/05/2015 10:00 PM','mm/dd/yyyy hh12:mi aa ') ->blank output