diff --git a/erpnext/buying/doctype/purchase_order/test_purchase_order.py b/erpnext/buying/doctype/purchase_order/test_purchase_order.py
index 08f5d8b..1712369 100644
--- a/erpnext/buying/doctype/purchase_order/test_purchase_order.py
+++ b/erpnext/buying/doctype/purchase_order/test_purchase_order.py
@@ -118,6 +118,73 @@
 		self.assertEqual(po.get("items")[0].amount, 1400)
 		self.assertEqual(get_ordered_qty(), existing_ordered_qty + 3)
 
+	
+	def test_add_new_item_in_update_child_qty_rate(self):
+		po = create_purchase_order(do_not_save=1)
+		po.items[0].qty = 4
+		po.save()
+		po.submit()
+		pr = make_pr_against_po(po.name, 2)
+
+		po.load_from_db()
+		first_item_of_po = po.get("items")[0]
+
+		trans_item = json.dumps([
+			{
+				'item_code': first_item_of_po.item_code,
+				'rate': first_item_of_po.rate,
+				'qty': first_item_of_po.qty,
+				'docname': first_item_of_po.name
+			},
+			{'item_code' : '_Test Item', 'rate' : 200, 'qty' : 7}
+		])
+		update_child_qty_rate('Purchase Order', trans_item, po.name)
+
+		po.reload()
+		self.assertEquals(len(po.get('items')), 2)
+		self.assertEqual(po.status, 'To Receive and Bill')
+
+	
+	def test_remove_item_in_update_child_qty_rate(self):
+		po = create_purchase_order(do_not_save=1)
+		po.items[0].qty = 4
+		po.save()
+		po.submit()
+		pr = make_pr_against_po(po.name, 2)
+
+		po.reload()
+		first_item_of_po = po.get("items")[0]
+		# add an item
+		trans_item = json.dumps([
+			{
+				'item_code': first_item_of_po.item_code,
+				'rate': first_item_of_po.rate,
+				'qty': first_item_of_po.qty,
+				'docname': first_item_of_po.name
+			},
+			{'item_code' : '_Test Item', 'rate' : 200, 'qty' : 7}])
+		update_child_qty_rate('Purchase Order', trans_item, po.name)
+
+		po.reload()
+		# check if can remove received item
+		trans_item = json.dumps([{'item_code' : '_Test Item', 'rate' : 200, 'qty' : 7, 'docname': po.get("items")[1].name}])
+		self.assertRaises(frappe.ValidationError, update_child_qty_rate, 'Purchase Order', trans_item, po.name)
+
+		first_item_of_po = po.get("items")[0]
+		trans_item = json.dumps([
+			{
+				'item_code': first_item_of_po.item_code,
+				'rate': first_item_of_po.rate,
+				'qty': first_item_of_po.qty,
+				'docname': first_item_of_po.name
+			}
+		])
+		update_child_qty_rate('Purchase Order', trans_item, po.name)
+
+		po.reload()
+		self.assertEquals(len(po.get('items')), 1)
+		self.assertEqual(po.status, 'To Receive and Bill')
+
 	def test_update_qty(self):
 		po = create_purchase_order()
 
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index 6150516..86f5d53 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -1155,6 +1155,25 @@
 	child_item.base_amount = 1 # Initiallize value will update in parent validation
 	return child_item
 
+def check_and_delete_children(parent, data):
+	deleted_children = []
+	updated_item_names = [d.get("docname") for d in data]
+	for item in parent.items:
+		if item.name not in updated_item_names:
+			deleted_children.append(item)
+
+	for d in deleted_children:
+		if parent.doctype == "Sales Order" and flt(d.delivered_qty):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been delivered").format(d.idx, d.item_code))
+
+		if parent.doctype == "Purchase Order" and flt(d.received_qty):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been received").format(d.idx, d.item_code))
+		
+		if flt(d.billed_amt):
+			frappe.throw(_("Row #{0}: Cannot delete item {1} which has already been billed.").format(d.idx, d.item_code))
+
+		d.cancel()
+		d.delete()
 
 @frappe.whitelist()
 def update_child_qty_rate(parent_doctype, trans_items, parent_doctype_name, child_docname="items"):
@@ -1163,6 +1182,8 @@
 	sales_doctypes = ['Sales Order', 'Sales Invoice', 'Delivery Note', 'Quotation']
 	parent = frappe.get_doc(parent_doctype, parent_doctype_name)
 
+	check_and_delete_children(parent, data)
+
 	for d in data:
 		new_child_flag = False
 		if not d.get("docname"):
diff --git a/erpnext/public/js/utils.js b/erpnext/public/js/utils.js
index f363999..3f444f8 100755
--- a/erpnext/public/js/utils.js
+++ b/erpnext/public/js/utils.js
@@ -458,7 +458,8 @@
 					fieldname:"item_code",
 					options: 'Item',
 					in_list_view: 1,
-					read_only: 1,
+					read_only: 0,
+					disabled: 0,
 					label: __('Item Code')
 				}, {
 					fieldtype:'Float',
diff --git a/erpnext/selling/doctype/sales_order/test_sales_order.py b/erpnext/selling/doctype/sales_order/test_sales_order.py
index feb6b76..d8e9a63 100644
--- a/erpnext/selling/doctype/sales_order/test_sales_order.py
+++ b/erpnext/selling/doctype/sales_order/test_sales_order.py
@@ -321,7 +321,12 @@
 		create_dn_against_so(so.name, 4)
 		make_sales_invoice(so.name)
 
-		trans_item = json.dumps([{'item_code' : '_Test Item 2', 'rate' : 200, 'qty' : 7}])
+		first_item_of_so = so.get("items")[0]
+		trans_item = json.dumps([
+			{'item_code' : first_item_of_so.item_code, 'rate' : first_item_of_so.rate, \
+				'qty' : first_item_of_so.qty, 'docname': first_item_of_so.name},
+			{'item_code' : '_Test Item 2', 'rate' : 200, 'qty' : 7}
+		])
 		update_child_qty_rate('Sales Order', trans_item, so.name)
 
 		so.reload()
@@ -330,6 +335,48 @@
 		self.assertEqual(so.get("items")[-1].qty, 7)
 		self.assertEqual(so.get("items")[-1].amount, 1400)
 		self.assertEqual(so.status, 'To Deliver and Bill')
+	
+	def test_remove_item_in_update_child_qty_rate(self):
+		so = make_sales_order(**{
+			"item_list": [{
+				"item_code": '_Test Item',
+				"qty": 5,
+				"rate":1000
+			}]
+		})
+		create_dn_against_so(so.name, 2)
+		make_sales_invoice(so.name)
+
+		# add an item so as to try removing items
+		trans_item = json.dumps([
+			{"item_code": '_Test Item', "qty": 5, "rate":1000, "docname": so.get("items")[0].name},
+			{"item_code": '_Test Item 2', "qty": 2, "rate":500}
+		])
+		update_child_qty_rate('Sales Order', trans_item, so.name)
+		so.reload()
+		self.assertEqual(len(so.get("items")), 2)
+
+		# check if delivered items can be removed
+		trans_item = json.dumps([{
+			"item_code": '_Test Item 2',
+			"qty": 2,
+			"rate":500,
+			"docname": so.get("items")[1].name
+		}])
+		self.assertRaises(frappe.ValidationError, update_child_qty_rate, 'Sales Order', trans_item, so.name)
+
+		#remove last added item
+		trans_item = json.dumps([{
+			"item_code": '_Test Item',
+			"qty": 5,
+			"rate":1000,
+			"docname": so.get("items")[0].name
+		}])
+		update_child_qty_rate('Sales Order', trans_item, so.name)
+		
+		so.reload()
+		self.assertEqual(len(so.get("items")), 1)
+		self.assertEqual(so.status, 'To Deliver and Bill')
 
 
 	def test_update_child_qty_rate(self):