diff --git a/doc/src/refmanual/replace_if.rst b/doc/src/refmanual/replace_if.rst
index 7b0e6b9..a647153 100644
--- a/doc/src/refmanual/replace_if.rst
+++ b/doc/src/refmanual/replace_if.rst
@@ -11,6 +11,7 @@ Synopsis
     template<
           typename Sequence
         , typename Pred
+        , typename NewType
         , typename In = |unspecified|
         >
     struct replace_if