Dear [Name]:

No matter how thoroughly we have you insured, there is always an advantage to having a loss control specialist perform a double check. We have an opportunity to arrange for an [describe] from [name of insurance company] to visit your premises.

If it is convenient, will you please set aside an hour or so on [date] at about [time] for our visit?

You may also wish to have your [name or title] there. I'll call to confirm.

Sincerely,

P.S. If there is a more convenient time or date, please do not hesitate to call.