Send new renter agreement and letters when a property changes

The welcome letter goes out as soon as they book.  So, if the property changes then the welcome letter they received addresses the old home.  We will have to manually send them a new renter agreement and a new welcome letter.
We have 72 homes and are growing to 150 this year.  It would be nice if we could have an automatic letter that is triggered when the booking changes properties so any letters that were sent would triggers new letters to go out.  I know this seems like a minimal task, but look at all the messages we get in a day from renters, upcoming guests, and potential guests.  Anything to make this easier for us is truly appreciated.  

Wouldn't this already be possible.  Create a trigger of when the booking changes.  Because after it changes, it send the welcome for that property.