Commercial real estate and step up basis creative financing

[Carl Cheung]

Hi all, I have an office in a building where it will go on sale once the owner passes. They said it is in a trust and structured so that it can't be sold until the owner's death? I'd like to approach them with purchasing the building but I'm assume they're not wanting to sell it until after the owner's death due to the step up basis.
I have first right of refusal but what type of creative financing can I offer so that we agree upon a sale and price beforehand? Thanks