diff --git a/reference/session/functions/session-name.xml b/reference/session/functions/session-name.xml
index 6f02ce5714..b3e2db10e0 100644
--- a/reference/session/functions/session-name.xml
+++ b/reference/session/functions/session-name.xml
@@ -14,7 +14,9 @@
   </methodsynopsis>
   <para>
    <function>session_name</function> returns the name of the current
-   session or changes the name if <parameter>name</parameter> is given. 
+   session. If <parameter>name</parameter> is given,
+   <function>session_start</function> will update the session name and return
+   the <literal>old</literal> session name.
   </para>
   <para>
    The session name is reset to the default value stored in