diff --git a/acm/README.md b/acm/README.md
index 9dbac16..36797c0 100644
--- a/acm/README.md
+++ b/acm/README.md
@@ -22,7 +22,7 @@ module "cert" {
 
   ## optional
   ## add additional names to SAN
-  # certificate_san    = "otherdomain.domain.census.gov"
+  # certificate_san    = [ "otherdomain.domain.census.gov" ]
 }
 
 # associating it with the ALB listener
diff --git a/acm/main.tf b/acm/main.tf
index 8320156..85c4a20 100644
--- a/acm/main.tf
+++ b/acm/main.tf
@@ -22,7 +22,7 @@
 *
 *   ## optional
 *   ## add additional names to SAN
-*   # certificate_san    = "otherdomain.domain.census.gov"
+*   # certificate_san    = [ "otherdomain.domain.census.gov" ]
 * }
 *
 * # associating it with the ALB listener