I ended up using the code below and it works for what I'm trying to do. Thanks for your input and I've saved it as well.

Case When [Hour] > 12 Then convert(varchar(2),[Hour]-12) + ' PM' When [Hour] = 12 Then convert(varchar(2),[Hour]) + ' PM' When [Hour] < 12 Then convert(varchar(2),[Hour]) + ' AM' End,

In a subquery I'm pulling the field [Hour] as:

[Hour]= datepart(hh,a.CallDateEnded),

Regards,

John