Real English Forty-Eight: RSVP

After we moved,  I visited my neighbor's house a few times. 
(Btw, his name is Mr. S.)  
In November, when I went to his house one time with Taiga, his wife invited my family to their house for a Christmas Party.
The following is our conversation:

Mrs. S:  Why don't we have a Christmas party? 
Me: That's sounds great.  But we're not Christian.
Mrs. S: Neither are we.  So, when is good for you?
Me: We are usually free on Sundays and national holidays.  But I have to check with my wife...
Mrs. S:  I understand, no problem. We will also check our schedule.

Two weeks later, Mr. S and his two daughters knocked on my door.
I was VERY embarrassed because I had just gotten out of the bath with Taiga, and I was wearing my wife's robe! It is purple and very short!!  When I opened the door, Mr. S must have thought I was a lunatic! His two daughters looked shocked and couldn't hold in their laughter.
After they all stopped giggling, the below is what we said:

Mr. S:  Is this a bad time?
Me: Not really.  But I just got out of the bath with Taiga, and I am alone, so my hands are kinda tied.
Mr. S:  Gotcha! Then I will make it quick.  
Me: Thanks!
Mr. S:  Here is an invitation to the Christmas Party we talked about the other day.  Please RSVP by next Sunday, the 7th.
Me:  Thank you very much!  You didn't have to come over here, in the dark, in the cold, just to give me the invitation...you could have just called!
Mr. S: Not a problem.  We wanted to get some fresh air anyway. 
(Then with a smirk on his face)
Mr. S:  Do you always wear this purple robe around the house?!?
Me: No!!! Get outta here! I'll contact you soon!  Later!