You could apply for a re-zone, or leave the res zoning in place, but get a variance for your specific use.
If you are keeping the house and have a specific business tenant in mind the variance might be the way to go.
That way you have the best of both worlds - if the advantage of business use evaporated in the future and res use was preferable financially, you would not have to go through a full re-zone again. Another thought is to get the variance for a mixed use or live / work space.
The full re-zone might be have higher expenses and requirements than a variance.
I'd like to see the property pitch in an email when you write it.