Earlier in the year, I mentioned to a close family frend to save the date for our wedding, but I didn't know she had already planned to take her kids to the US Open in NY on our day. Plane tickets, hotel, event tickets... everything booked. Today, I received the cake serving set we had on our registry (and I think she also got us pots and pans). Obviously, I will send her a nice thank you card, but do I still send an invitation? We didn't send STDs, and I know the standard "their plans may have changed" probably applies, but I just wanted to get some opinions.