Mvc disable validation of some controls

<pre lang="HTML">@using (Html.BeginForm("Index","Home",FormMethod.Post))
    {
	@Html.LabelFor(model => model.Name)
                @Html.TextBoxFor(model => model.Name , new { @class = "form-control" , @id = "txtbillingamount" })
	
	 @Html.LabelFor(model => model.Amount)
                @Html.TextBoxFor(model => model.Amount , new { @class = "form-control" , @id = "txtbillingamount" })
				
				  <button type="submit" name="command" value="request" >Next</button>
				  
				     @if (Model != null)
            {
               
                    <table class="table table-hover table-bordered table-striped">
                        <thead class="hbl-thead">
                            <tr>
                                <th> Title</th>
                                <th> Number</th>
                                <th>Amount</th>
                                
                            </tr>
                        </thead>
                        <tbody>
                            <tr>
                                <td>@Html.DisplayFor(model => model.ToAccountTitle)@Html.HiddenFor(model => model.ToAccountTitle)  </td>
                                <td>@Html.DisplayFor(model => model.RecieverMobileNumber)@Html.HiddenFor(model => model.RecieverMobileNumber)</td>
                                <td>@Html.DisplayFor(model => model.Amount)@Html.HiddenFor(model => model.Amount)</td>                                
                            </tr>
                        </tbody>
                    </table>
                
                <div class="col-lg-6 col-md-6 col-sm-12 col-xs-12">

                    <div class="form-group input-group-sm">
                        @Html.LabelFor(model => model.PIN)
                        @Html.PasswordFor(model => model.PIN , new { @class = "form-control" })                        
                    </div>
                    <button type="submit" name="command" value="payment">Submit</button>

                </div>
            }
	}

public ActionResult Index(MyModel model , string command){
  if (ModelState.IsValid)
          {
              if (command == "request")
              {
              //Return data in model to fill Table
              }
              else if (command == "payment")
              {

              }
              }

              return View(model);
}