The remedy may vary slightly depending.I would put IRS compliance ahead of a clear chain of title, and would ensure that the title attorney produces and records the necessary documents to clarify the chain of title as an amendment to any new deed.I would also get documentation from the title attorney regarding the error.  

You should ask your agent about writing up an Amend/Extend agreement, that extends the closing date.

Require everyone to sign a lease amendment which will clarify the changes you are making to the lease, or terminate the old lease and enter into a new one with the tenant who stays. 

Or should I just make an amendment to the current lease? 

Account Closed In an earlier post I suggested that we should have a law or amendment that requires English to be the official language of the country.

But this is surpassingly irrelevant as I have no duty to anyone but myself to enforce the terms of my lease and I am free to amend those terms to make them more permissive at any moment.Under these facts I don't think the case is susceptible of a neat solution.

The tenant has already signed a lease, and has not asked we amend the pet rent.

Going to amend a new lease agreement tonight!

One of the things that I always put into my contracts is a clause that states that amendments to the contract can be made by following a predetermined process and getting all the signatories to sign the amendment.

If your lease is vague or doesn't include wording about a tenant's ability to alter or do repairs to the property only with your written consent, see if it is possible to amend the lease; the tenant-landlord laws of your state  may allow you to serve a notice so this does not happen again.