diff --git a/spyglass_plugin_xls/cli.py b/spyglass_plugin_xls/cli.py
index fec0fcf..31835f4 100644
--- a/spyglass_plugin_xls/cli.py
+++ b/spyglass_plugin_xls/cli.py
@@ -100,6 +100,13 @@ MANIFEST_DIR_OPTION = click.option(
     required=False,
     help='Path to place created manifest files.')
 
+FORCE_OPTION = click.option(
+    '--force',
+    'force',
+    is_flag=True,
+    default=False,
+    help="Forces manifests to be written, regardless of undefined data.")
+
 
 @excel.command('intermediary',
                short_help='generate intermediary',
@@ -135,6 +142,7 @@ def generate_intermediary(*args, **kwargs):
 @SITE_NAME_CONFIGURATION_OPTION
 @TEMPLATE_DIR_OPTION
 @MANIFEST_DIR_OPTION
+@FORCE_OPTION
 def generate_manifests_and_intermediary(*args, **kwargs):
     process_input_ob = \
         spyglass.cli.intermediary_processor('excel', **kwargs)
@@ -147,5 +155,6 @@ def generate_manifests_and_intermediary(*args, **kwargs):
         LOG.debug("Skipping dump for intermediary yaml")
 
     LOG.info("Generating site Manifests")
-    processor_engine = SiteProcessor(intermediary_yaml, kwargs['manifest_dir'])
+    processor_engine = SiteProcessor(
+        intermediary_yaml, kwargs['manifest_dir'], kwargs['force'])
     processor_engine.render_template(kwargs['template_dir'])