Dear John and Paula,
I'm really sorry but I can't arrive to you in July. I've broken my leg yesterday and I can't move anywhere.
I was playing basketball when I tripped on something and then my leg broke. Doctors said that they'll put a moulage and I won't be able to go out my flat for about month.
I think I can visit you in 2nd September but i need your agree.
Hope this incident won't screw your vacation plans.
Send me photos from the holidays.
Best wishes, XYZ