To do this legally, I know plans need to be drawn and submitted to the Planning Board.

Hi @Heather Bailey something to consider with this is legal mother/daughter may not mean legal duplex. 

What is the legal mechanism?

If you need financial help, ask under the "Finance, Tax, and Legal" forum.

You and your legal, tax and financial advisors should review this transaction in greater detail, especially the PLRs, to ensure you understand the significant risks involved and are structuring the transaction as close as possible to the PLRs to mitigate some of the risks.

Hello Doug, I am not a real estate attorney nor is this legal advice.Unless someone's state has specific laws banning contract assignments you should be fine doing the following.  

In Illinois, when an agent does that, there are functions normally expected of the realtor that they are legally prohibited from doing.

He strongly advised me to take legal action.Please don’t fall for this scam.

If you know of any legal entity in TX that can help in a case where GP is not doing their job (maybe a branch of SEC), please let me know.TIA

The contract was a simple 3 page one and I wrote this in.Also, it is a single family being rented as a rooming house (which is technically not legal here).