correct wording
diff --git a/source/fortress/user-guide/4.2-check-access.md b/source/fortress/user-guide/4.2-check-access.md
index 1760d37..c8cf682 100644
--- a/source/fortress/user-guide/4.2-check-access.md
+++ b/source/fortress/user-guide/4.2-check-access.md
@@ -15,7 +15,7 @@
```
Perform user RBAC authorization. This function returns a Boolean value meaning whether the subject of a given session is allowed
-not to perform a given operation on a given object.
+to perform a given operation on a given object.
The function is valid if and only if:
- the session is a valid Fortress session
