SQL Block Updating OrderID / ItemID

This time its like this: i have a table (orderId, itemId, CustomerId, productId, quantity, start_date, end_date, oldRef) here are some of the values:

2477, 3, 201, 111, 1,19-MAR-93,14-APR-93
2477,4,201,112,1,19-MAR-93,14-APR-93
2478,1,201,113,1,19-MAR-93,14-APR-93
2478,2,201,110,19-Mar-93,14-APR-93

Now as you can see that order_Id is different however order_date and ship_date both match. Now what i want to do is to give them a new orderId, re-arrange itemId if ship_date and order_date match for each customer so the ex above should come out like this:

1, 1, 201, 111, 1,19-MAR-93,14-APR-93
1,2,201,112,1,19-MAR-93,14-APR-93
1,3,201,113,1,19-MAR-93,14-APR-93
1,4,201,110,19-Mar-93,14-APR-93

I have created a pl/sql block. It has a cursor that loops around each row of table. Then it stores orderdate, shipdate and customerId. it also has a itemId variable and orderDate variable. OrderDate variable takes its value from orderId sequence and itemId is just a number that increments itself. when orderdate,shipdate&customerId are the same, i just update the itemId, if they differ or customer_id changes i get a new order_id, update the variables (orderdate,shipdate,customerid,itemId)

DECLARE
cursor c1 is
SELECT
*
FROM
ph2_item
order by
customer_id,
ship_date,
order_date
for update;
[code]...