I recently did this, Erika and that is exactly how I handled it - I represented the tenant/buyer and recommended the landlord/seller hire his own agent (and he did). 

represent the past client (buyer) who needs, in my opinion, representation beyond that of the seller....all buyers need guidance and the seller will agree to a co-broke fee...

I went through this a couple of years ago.

I made it very clear that I was going to ONLY represent the tenant/buyer (written disclosure) and the seller had an option to get their own counsel. I also made it clear what my commission was going to be, paid out of the purchase price.

The seller decided not to use anyone else...and no, I did not become a transaction broker, dual agent or any combination...I still represented ONLY the tenant/buyer.  

It was not my job to advise the seller about anything...

Eve

  What Eve said.   Mike & Eve Alexander 

Write a contract, represent both as a dual agent. Make the sale.

Submit a contract as the buyer agent.

The tenant is your client, yes?
Here in the magickal land of AZ, if I had no relationship with the landlord, I'd probably secure a compensation agreement and do that . . . 
If I did have a decent rapport with the landlord, I'd ask him/her if it would be easier for me to oversee all - of course, welcoming them to have their own rep or attorney. 

Erika,

You have great answers here.  A

I would represent the tenant & then have the seller get an attorney to help on his side (IL).

This always depends on so many different factors, but I would allow the seller to suggest what you mention as you might be leaving money on the table.

First I would make sure the tenant can actually get a loan to buy the property. Once approved and I have proof of funds in hand, I would approach the landlord.  I would make it clear that I would not represent the landlord - only the buyer. 

Get a "One Time Showing Agreement," so you are renumerated for your services. From there, represent you client and let the seller do as they please.

Since the tenant is a past client it seems logical for you to represent them and let the seller decide how he wants to be represented on his side of the transaction.

represent the Buyer and Seller may choose to be unrepresented or have representation of their choice.

Since you are a Texas REALTOR® I would approach the seller give them an IABS and the REGISTRATION AGREEMENT BETWEEN BROKER AND OWNER (TAR FORM 2401), represent the buyer only and the property owner only has to pay you, unless of course he wants representation.

This could beome sticky if you say too much too soon. After all, why does the seller need you if the tenant is already sold on the home? 

In CA we're allowed to do dual agency and I LOVE it!.  I'm assuming you rented the house out for the landlord.  I'd first ask the landlord if he's interested in selling.  I'd have no trouble representing both parties.  Since I own most of the rentals I represent, I'd be all parties in the transaction EXCEPT the buyer!

I had one tenant ask me if I was willing to sell.  I said no and helped him buy another house.

It depends on the scenario,  the particulars and the participants plus any state or individual brokerage requirements.  Good luck to all.

Before you do, show them some alternatives. Odds are they will stay with the place they are in, but provide some alternatives in the price range. Yes, represent the buyer, they are your client. Ask the seller to handle the commission. 

Flat fee to write the deal up. Represent the buyer and use a seller's fee agreement to ensure you get paid. 

Well, yes... assuming your past client is wanting your representation and either the client or seller pay your commission.

Lately, I have had this pop up more than a few times.    But, the seller was usually my client, and was a transaction broker for the deal.

I would have them try and make a deal and then be a facilitator.  Now if that did not work, then I rep the buyers

Sounds like the plan Erika Rae Albert, Austin Real Estate Expert !

I would definitely represent the buyer and suggest the Seller retain his own agent.  If Seller does not retain an agent, ensure you get something signed by the Seller agreeing to pay you commission... before you submit the offer.

I would work something out with the landlord.

Erika Rae Albert, Austin Real Estate Expert - sometimes the landlord prefers that no agents are involved. 

You can talk to the landlord directly anyways.

I have done that and sometimes the seller has hired an agent or an attorney and sometimes they went unrepresented. 

I would refer the buyer and represent the seller.

Offer to work at at 50% discount to bring the deal together.

I've done this a few times.

I typically only represent the party I have the relationship with and refer the other party to my team member; which is an arm's length dual agency with separate representation under one roof.

My answer in California: talk to both parties and discuss the alternatives. I would represent both if both are agreeable. If not, I would prefer to represent the buyer who is my past client and, apparently, the instigator of this possible transaction. Make sure you have an agreement in place to guarantee that you get paid.

You can represent the renter if the dialogue already got started. Just represent one side.  

If your state doesn't allow dual agency, your client is the buyer.

I would try to represent both.