You can edit some details associated with an item. Specifically the price, piece count, turn around time and price list. To do so you'll:
Go to Set Up > Services to access the Services Page.
Select the parent category (ie dry cleaning) of the item you'll be editing
Choose the row for the item you'll be modifying
Enter .the new values
Click Save
To edit the name of an item, simply create a new item with the correct name and delete the old item.