diff -r 5d574b92203c -r d4977b04ef98 hgext/evolve.py
--- a/hgext/evolve.py	Mon Sep 22 17:27:57 2014 -0700
+++ b/hgext/evolve.py	Tue Sep 30 10:27:11 2014 -0500
@@ -779,7 +779,7 @@
     if not orig.p2().rev() == node.nullrev:
         raise util.Abort(
             'no support for evolving merge changesets yet',
-            hint="Redo the merge and use `hg prune` to obsolete the old one")
+            hint="Redo the merge and use `hg prune <old> --succ <new>` to obsolete the old one")
     destbookmarks = repo.nodebookmarks(dest.node())
     nodesrc = orig.node()
     destphase = repo[nodesrc].phase()