title: Pandas resample by first day in my data
body: <p>I have a Yahoo finance daily stock price imported in a pandas dataframe. I want to use <code>.resample()</code> to convert it to the monthly stock price by taking the price of the first QUOTED daily price of each month.</p>
  
  <pre><code>.resample('MS', how='first')
  </code></pre>
  
  <p>returns the correct price of each month <strong>but</strong> it changes the index to the first day of the month while in general the first day of a month for a quoted price maybe 2nd or 3rd of the month because of holidays and weekends.</p>
  
  <p>How can I use <code>resample()</code> by only resampling the existing dates and not changing them?</p>