I made custom module on Design manager. It uses contact property and replace with default value property is not set (blank). Tried 2 implementation case but could not work.
output of code is blank.
case 1
<td style="width: 50%; padding-right: 14px; text-align: left; font-size: 12px; padding-bottom: 30px; line-height: 1.5em;" valign=top class="k-480-col mk-padding">
<a href="{{ contact.booking_recomended_listing_1_url|default('example.com') }}">
<img src="{{ contact.booking_recomended_listing_1_image|default('example.jpg', true) }}" style="width: 296px; height: 180; object-fit: contain; border: none;" width="{{ widget.image_left.width }}" alt="{{ widget.image_left.alt }}">
<h2 style="font-size: 14px; margin-top: 15px;">{{ contact.booking_recomended_listing_1_name|default('example name', true) }}</h2>
{{ contact.booking_recomended_listing_1_access|default('example text', true) }}
</a>
</td>
case 2
<td style="width: 50%; padding-left: 14px; text-align: left; font-size: 12px; padding-bottom: 30px; line-height: 1.5em;" valign=top class="k-480-col k-480-padding">
{% if contact.booking_recomended_listing_2_url != "CONTACT.BOOKING_RECOMENDED_LISTING_2_URL" %}
<a href="{{contact.booking_recomended_listing_2_url}}">
<img src="{{contact.booking_recomended_listing_2_image}}" style="width: 296px; height: 180; object-fit: contain; border: none;" width="{{ widget.image_left.width }}" alt="{{ widget.image_right.alt }}">
</a>
<h2 style="font-size: 14px; margin-top: 15px;"><a href="{{contact.booking_recomended_listing_1_url}}">{{ contact.booking_recomended_listing_2_name }}</a></h2>
{{ contact.booking_recomended_listing_2_access }}
{% else %}
<a href="example.com">
<img src="example.JPG" style="width: 296px; height: 180; object-fit: contain; border: none;" width="{{ widget.image_left.width }}" alt="{{ widget.image_left.alt }}">
</a>
<h2 style="font-size: 14px; margin-top: 15px;"><a href="example.com">example name</a></h2>
example text
{% endif %}
</td>