Changing locks on a wholesale property

[Account Closed]

So I recently acquired a contract for a property that I am looking to wholesale. The only issue is that the owner lives out of state and cannot let me into the property in order to take current photos, do my personal inspection, and show the property to buyers. The owner gave permission to go ahead and have a locksmith come out and change the locks but I am assuming the locksmith will want some form of proof of ownership. I'm guessing this is something people deal with all the time, but I am just curious how you go about proving to the locksmith that you have permission from the owner?