2 time formats in excel issue with date

I have an excel data with 5000 rows. I need to filter on data however as the data has been pulled from Oracle database it has been captured with date and time stamp. Now I need to filter the data on only time basis as date is the same i.e. 31st March. So there are 2 issues:- 1) How should I filter the data only basis time. 2) the other issue is the time has been captured in 2 ways- 9:01 pm & 21:01 pm. Can you please advice on to combined these 2 time frame formats into 1 and apply filter. Thank you.