title: How do I change the add to cart text for specific variations in WooCommerce?
body: <p>In my WooCommerce store I have simple products and variable products, both simple products and variations have a meta value of 'pre_order' which is yes/no.</p>
  
  <p>If this option is set on the backend I want to have the add to cart button say 'Pre-Order' as opposed to 'Add To Cart'.</p>
  
  <p>For simple products I have had no issue changing this using filters or editing file templates, variations seem much trickier though...</p>
  
  <p>When variation options are selected then the price and sku updates, during this process I also want to check the meta value mentioned above and if that variation has the meta value pre order of 'yes' then I would also like to change the button text but I cannot find a way to do so!</p>