to do want you want would require the assistance of a real estate lawyer since you don't own it and since your son's consent would be needed. In addition, there are major gift tax and income tax issues. For example, what you gifted to him would now have to be gifted d back to you. The IRS may deem the original gift invalid and make you responsible for reporting the rental activity on your taxes for the original acquisition date. As the grantors to the revocable (grantor) trust, you would be the ones under the tax laws required to report the activity on your tax return even if he got the rent and made all the payments. (possibly requiring annual gift tax filings)
I don't see any reason to do what you suggest and do so will complicate tax compliance for everyone.
