diff --git a/selling/doctype/lead/lead.py b/selling/doctype/lead/lead.py
index c336fe2..571cdfd 100644
--- a/selling/doctype/lead/lead.py
+++ b/selling/doctype/lead/lead.py
@@ -97,7 +97,6 @@
 		return webnotes.conn.get_value('Sales Email Settings',None,'email_id')
 
 	def on_trash(self):
-		webnotes.conn.sql("""delete from tabCommunication where lead=%s""",
-			self.doc.name)
+		webnotes.conn.sql("""update tabCommunication set lead=null where lead=%s""", self.doc.name)
 		webnotes.conn.sql("""update `tabSupport Ticket` set lead='' where lead=%s""",
 			self.doc.name)