Simply replace the unfilled areas such as "" and "[date]" with your information.
We have assigned [name of rep] as our new representative for your area. [Name of rep] has been with our firm for quite some time and is extremely experienced in all aspects of our production.
[name of rep] will be coming to [name of city] on [date] and will be calling on you in the morning if that doesn't conflict with your schedule.
If there is any problem with that date, please let us know.