Hi Margaret,
You may try to edit the checkout page (booking confirmation) and place a contact form instead of the [mphb_checkout] shortcode or Checkout Form block that class a checkout form on the front-end.
However could you please let us know why you do not want to use the checkout page that is generated by the plugin? If you wish to review each reservation manually you may switch to another confirmation mode – by admin manually at Accommodation > Settings.
best regards,
J. Davis