How to convert select dropdown to Multiple Checkbox?

I want to convert below dropdown code into multi select checkbox value. I am using wordpress and below code is coming from third party website. I don't have any access to that third party website.

<div class="facilities">
   <span class="label">Facilities</span>
   <span class="input">
      <select>
         <option value="">--- All ---</option>
         <option value="39945">Internet</option>
         <option value="39946">Swimming Pool</option>
         <option value="39947">Beach</option>
         <option value="39948">B&B</option>
         <option value="39949">Restaurant</option>
      </select>
   </span>
</div>

Looking for some solution with WordPress where I can change third party code after DOM Ready and change the code in multiple checkbox