diff --git a/presence/conversation.rkt b/presence/conversation.rkt
index dcd0bb2..7cbbda2 100644
--- a/presence/conversation.rkt
+++ b/presence/conversation.rkt
@@ -24,7 +24,7 @@
 	 (struct-out topic)
 	 topic-publisher
 	 topic-subscriber
-	 co-role
+	 co-roles
 	 co-topic
 
 	 ;; Reexported from unify.rkt for convenience
@@ -245,20 +245,20 @@
   (and es ;; some threads are not standard-threads
        (exit-status-exception es)))
 
-(define (co-role r)
+(define (co-roles r)
   (case r
-    [(publisher) 'subscriber]
-    [(subscriber) 'publisher]
+    [(publisher) '(subscriber)]
+    [(subscriber) '(publisher)]
     [else #f]))
 
-(define (co-topic t)
-  (struct-copy topic t [role (co-role (topic-role t))]))
+(define (co-topic t new-role)
+  (struct-copy topic t [role new-role]))
 
 (define (refine-topic remote-topic new-pattern)
   (struct-copy topic remote-topic [pattern new-pattern]))
 
 (define (roles-intersect? l r)
-  (eq? l (co-role r)))
+  (memq l (co-roles r)))
 
 ;; Both left and right must be canonicalized.
 (define (topic-intersection left right)
diff --git a/presence/test-conversation.rkt b/presence/test-conversation.rkt
index 040106b..4e36d7d 100644
--- a/presence/test-conversation.rkt
+++ b/presence/test-conversation.rkt
@@ -57,7 +57,9 @@
 				[(says (and specific-topic (topic 'publisher _ _)) _)
 				 (write `(,name acking) o)
 				 (newline o)
-				 (send handle say (co-topic specific-topic) (list name 'ack))]
+				 (send handle say
+				       (co-topic specific-topic 'subscriber)
+				       (list name 'ack))]
 				[_ (void)])
 			      (flush-output o)
 			      (loop)))