title: Time data does not match format '%yyyy-%mm-%dd
body: <p>I have the column &quot;date of registration&quot; in the below format.</p>
  <pre><code>array(['01JAN2018:00:00:00.000000000', '01JAN2019:00:00:00.000000000',
     '01JAN2020:00:00:00.000000000', ...,
     '09FEB2018:00:00:00.000000000', '09FEB2019:00:00:00.000000000',
     '09FEB2020:00:00:00.000000000'], dtype=object)
  </code></pre>
  <p>I am trying to convert this to the below format.</p>
  <pre><code>array(['1993-04-29', '1993-04-15', ..., '2019-08-29', '2019-08-30',
     '2019-08-31'], dtype=object)
  </code></pre>
  <p>I tried this conversion using to_datetime function but I get the error &quot;ValueError: time data '01JAN2018:00:00:00.000000000' does not match format '%yyyy-%mm-%dd' (match)&quot;.</p>