To make changes to addresses, items/dates, or greetings after you've already entered them and moved on:
Select the recipient from the recipient drop-down that you need to make changes to
Press Tab
Press F2 in the appropriate field (address, item number, date, greeting)
Pressing F2 in the address field will open the recipient page back up and allow you to change/update information.
Pressing F2 in the item number or date fields will present a window of options to choose from, like "change item" or "select arrival date."
Press F3 to save any changes you make.