Cross References can be edited after they are assigned.
Edit Cross References
1.Press the <Edit Cross References> link.
2.Select the field that has the cross reference to edit.
3.Modify the Cross Reference.
4.Press the <Save> button.
If you have a large number of Cross References you want to define in Excel, you can create them in a two-column list in Excel, copy them, then press the Paste Rows button to insert them into this Cross Reference screen.