title: IOB format merge
body: <p>I have a dataframe in IOB format as below:-</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Name</th>
  <th>Label</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>Alan</td>
  <td>B-PERSON</td>
  </tr>
  <tr>
  <td>Smith</td>
  <td>I-PERSON</td>
  </tr>
  <tr>
  <td>is</td>
  <td>O</td>
  </tr>
  <tr>
  <td>Alice's</td>
  <td>B-PERSON</td>
  </tr>
  <tr>
  <td>uncle</td>
  <td>O</td>
  </tr>
  <tr>
  <td>from</td>
  <td>O</td>
  </tr>
  <tr>
  <td>New</td>
  <td>B-LOCATION</td>
  </tr>
  <tr>
  <td>York</td>
  <td>I-LOCATION</td>
  </tr>
  <tr>
  <td>city</td>
  <td>I-LOCATION</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>I would like to convert into a new dataframe as below:-</p>
  <div class="s-table-container">
  <table class="s-table">
  <thead>
  <tr>
  <th>Name</th>
  <th>Label</th>
  </tr>
  </thead>
  <tbody>
  <tr>
  <td>Alan Smith</td>
  <td>PERSON</td>
  </tr>
  <tr>
  <td>Alice's</td>
  <td>PERSON</td>
  </tr>
  <tr>
  <td>New York city</td>
  <td>LOCATION</td>
  </tr>
  </tbody>
  </table>
  </div>
  <p>Any help is much appreciated!</p>