Use wfchitt.sql to change the internal name of an item type and update all references to the item type. See: Change the internal name of a workflow object.

Use the script as follows:

sqlplus <user> @wfchitt <old_type> <new_type> 
Enter password: <password>

Replace <old_type> with the current internal name of the item type, and replace <new_type> with the new internal name of the item type.