diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index ec68207ce73..5467e6c1b61 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -388,6 +388,14 @@ class stock_picking(osv.osv):
 			wf_service.trg_write(uid, 'stock.picking', pick.id, cr)
 		return True
 
+	def cancel_assign(self, cr, uid, ids, *args):
+		wf_service = netsvc.LocalService("workflow")
+		for pick in self.browse(cr, uid, ids):
+			move_ids = [x.id for x in pick.move_lines]
+			self.pool.get('stock.move').cancel_assign(cr, uid, move_ids)
+			wf_service.trg_write(uid, 'stock.picking', pick.id, cr)
+		return True
+
 	def action_assign_wkf(self, cr, uid, ids):
 		self.write(cr, uid, ids, {'state':'assigned'})
 		return True
@@ -688,6 +696,10 @@ class stock_move(osv.osv):
 		self.write(cr, uid, ids, {'state' : 'assigned'})
 		return True
 
+	def cancel_assign(self, cr, uid, ids, context={}):
+		self.write(cr, uid, ids, {'state': 'confirmed'})
+		return True
+
 	#
 	# Duplicate stock.move
 	#
diff --git a/addons/stock/stock_view.xml b/addons/stock/stock_view.xml
index 73d306735b0..6594ec9862d 100644
--- a/addons/stock/stock_view.xml
+++ b/addons/stock/stock_view.xml
@@ -461,17 +461,22 @@
 
 							<separator string="Move State" colspan="4"/>
 							<field name="state" select="1"/>
+							<group>
+								<button name="force_assign" string="Force assignation" states="confirmed" type="object"/>
+								<button name="cancel_assign" string="Cancel assignation" states="assigned" type="object"/>
+							</group>
 						</form>
 					</field>
 					<group colspan="4" col="7">
 						<label colspan="6"/>
 						<button type="action" name="%(move_split)d" string="Split move lines in two"/>
 					</group>
-					<group colspan="4" col="7">
+					<group colspan="4" col="8">
 						<field name="state" readonly="1"/>
 						<button name="button_confirm" string="Confirm Picking" states="draft"/>
-						<button name="action_assign" string="Assign Reservations" states="confirmed" type="object"/>
-						<button name="force_assign" string="Force Reservations" states="confirmed" type="object"/>
+						<button name="action_assign" string="Assign" states="confirmed" type="object"/>
+						<button name="force_assign" string="Force assignations" states="confirmed" type="object"/>
+						<button name="cancel_assign" string="Cancel assignations" states="assigned" type="object"/>
 						<button type="action" name="%(partial_picking)d" string="Make Picking" states="assigned"/>
 						<button name="button_cancel" string="Cancel Picking" states="assigned,confirmed,draft"/>
 					</group>
diff --git a/addons/stock/stock_workflow.xml b/addons/stock/stock_workflow.xml
index 42cd5c3468c..4e7eda0f0c9 100644
--- a/addons/stock/stock_workflow.xml
+++ b/addons/stock/stock_workflow.xml
@@ -49,6 +49,11 @@
 			<field name="act_to" ref="act_confirmed"/>
 			<field name="signal">button_confirm</field>
 		</record>
+		<record model="workflow.transition" id="trans_confirmed_assigned_back">
+			<field name="act_from" ref="act_assigned"/>
+			<field name="act_to" ref="act_confirmed"/>
+			<field name="condition">not test_assigned()</field>
+		</record>
 		<record model="workflow.transition" id="trans_confirmed_assigned">
 			<field name="act_from" ref="act_confirmed"/>
 			<field name="act_to" ref="act_assigned"/>
diff --git a/addons/stock/wizard/wizard_partial_picking.py b/addons/stock/wizard/wizard_partial_picking.py
index bc6704f920c..f8046ebe736 100644
--- a/addons/stock/wizard/wizard_partial_picking.py
+++ b/addons/stock/wizard/wizard_partial_picking.py
@@ -106,14 +106,15 @@ def _do_split(self, cr, uid, data, context):
 			price = data['form']['price%s' % move.id]
 			currency = data['form']['currency%s' % move.id]
 
-			new_price = currency_obj.compute(cr, uid, currency, user.company_id.currency_id.id, price)
-			new_std_price = ((product.standard_price * product.qty_available) + (new_price * qty))/(product.qty_available + qty)
-			product_obj.write(cr, uid, [product.id], {'standard_price': new_std_price})
+			if qty > 0:
+				new_price = currency_obj.compute(cr, uid, currency, user.company_id.currency_id.id, price)
+				new_std_price = ((product.standard_price * product.qty_available) + (new_price * qty))/(product.qty_available + qty)
+				product_obj.write(cr, uid, [product.id], {'standard_price': new_std_price})
 
 	for move in too_few:
 		if not new_picking:
 			new_picking = pick_obj.copy(cr, uid, pick.id, {'name' : '%s (splitted)' % pick.name, 'move_lines' : [], 'state':'draft'})
-		new_obj = move_obj.copy(cr, uid, move.id, {'product_qty' : data['form']['move%s' % move.id], 'product_uos_qty':data['form']['move%s' % move.id], 'picking_id' : new_picking, 'state': move.state, 'move_dest_id': False})
+		new_obj = move_obj.copy(cr, uid, move.id, {'product_qty' : data['form']['move%s' % move.id], 'product_uos_qty':data['form']['move%s' % move.id], 'picking_id' : new_picking, 'state': 'assigned', 'move_dest_id': False})
 		move_obj.write(cr, uid, [move.id], {'product_qty' : move.product_qty - data['form']['move%s' % move.id], 'product_uos_qty':move.product_qty - data['form']['move%s' % move.id]})
 
 	if new_picking:
@@ -126,9 +127,13 @@ def _do_split(self, cr, uid, data, context):
 	if new_picking:
 		wf_service.trg_validate(uid, 'stock.picking', new_picking, 'button_confirm', cr)
 	# Then we finish the good picking
-	picking_toclose = new_picking or pick.id
-	pick_obj.action_move(cr, uid, [picking_toclose])
-	wf_service.trg_validate(uid, 'stock.picking', picking_toclose, 'button_done', cr)
+	if new_picking:
+		pick_obj.action_move(cr, uid, [new_picking])
+		wf_service.trg_validate(uid, 'stock.picking', new_picking, 'button_done', cr)
+		wf_service.trg_write(uid, 'stock.picking', pick.id, cr)
+	else:
+		pick_obj.action_move(cr, uid, [pick.id])
+		wf_service.trg_validate(uid, 'stock.picking', pick.id, 'button_done', cr)
 	return {}
 
 class partial_picking(wizard.interface):