It appears that the "Home Selling in 02466" tag has sent you into the MA questions asked area.
02466 is Auburndale MA.
That being said, you can advertise anything, but I'd ask your attorney this question.
Also, if you are in MA, most P & S agreements have a paragraph where you are allowed to assign your interest before closing.
It usually requires a 7 day notice before the closing if you plan to do so.
Thus in theory, you could sell your "option" to buy the property that you have in place because of your P & S agreement.
I have not seen this done too often.
As for the advertising, I would disclose that this is a property that you have underagreement, and I would not mention what you plan to be selling after your re-construction, unless you already have the permit(s) in hand.
Again, your attorney can direct your efforts.
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