title: Convert datetime columns to a different timezone pandas
body: <p>I have two datetime columns which are naive when I read them into memory but which are in US/Eastern actually. I simply want to convert both of these columns to US/Central.</p>
  
  <p>I found a method which works but it seems like I am doing a workaround.
  I changed my call_start and call_end columns to be named 'start' and 'end' instead so I don't end up with duplicate column names. I then created a separate datetimeindex for each of these columns and reset the index.</p>
  
  <pre><code>aht.set_index(pd.DatetimeIndex(aht['start']).tz_localize('US/Eastern').tz_convert('US/Central'), inplace = True, drop = True)
  aht.index.names = ['call_start']
  aht = aht.reset_index()
  aht.set_index(pd.DatetimeIndex(aht['end']).tz_localize('US/Eastern').tz_convert('US/Central'), inplace = True, drop = True)
  aht.index.names = ['call_end']
  aht = aht.reset_index()
  </code></pre>
  
  <p>I end up getting:</p>
  
  <pre><code>                 call_end                  call_start              start                 end
  2016-01-13 06:05:01-06:00   2016-01-13 06:02:00-06:00   01/13/2016 07:02    01/13/2016 07:05
  2016-01-13 06:07:00-06:00   2016-01-13 06:03:16-06:00   01/13/2016 07:03    01/13/2016 07:07
  2016-01-13 06:09:13-06:00   2016-01-13 06:06:02-06:00   01/13/2016 07:06    01/13/2016 07:09
  2016-01-13 06:17:51-06:00   2016-01-13 06:06:20-06:00   01/13/2016 07:06    01/13/2016 07:17
  </code></pre>
  
  <p>Is this the best method? All other data is in central time so I just want to make sure that this file is too so when I merge files together it makes more sense. I do not care about having the actual timezone stamp there though - is there a way to easily strip it after I created my new columns?</p>