title: pandas from datetime64[ns] to object (python)
body: <p>I have the code show below, where, after to convert the column <code>closingdate</code> from <code>object</code> to <code>datetime</code> an operate with it,and after to created a new column named 'start' with the results, I need to converted this column <code>start</code> from <code>datetime</code> to <code>object</code> , before to convert it to json.</p>
  
  <p>If anyone can help I will highly appreciate it.Thanks in advance.</p>
  
  <pre><code>initial_data = sql(query1)
  initial_data['closingdate'] = pd.to_datetime(initial_data.closingdate)
  
  initial_data['start']=pd.to_datetime(initial_data.closingdate)+pd.to_timedelta(pd.np.ceil(initial_data.tenor1),unit='D')
  
  initial_data=initial_data[['dealid','title','tranch_structure','start']]
  initial_data['start']=pd.to_str(initial_data.start)
  
  
  initial_data =initial_data.to_json(orient='table')
  </code></pre>