Selling a financed car & release of liability?

I'm selling a financed vehicle and we're doing a bill of sale and i will user the buyers cash to mail in to Honda for the pay off amount.

The buyer will be taking the car until I get the title, but the car will already be paid off with a cashiers check from the buyer( i will be present with buyer when getting check)

so my question is do i fill the release of liability when he takes the vehicle with bill of sale? Or when i get the title and send him the title?

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