A consumer and Realtor can work together in four ways in the state of Alabama:
Buyer agency, the highest and best form of registration a Realtor can offer his/her clients. You have a separate agreement spelling out the terms and duration of the arrangement. You can offer opinion and interpretation of the data.
Transaction broker, a one page agreement stating that you will guide the documentation of the offer to the closing table. You can provide market info but you cannot interpret said data or give opinions. Once you do you are in agency regardless of the paper signed.
Limited Consensual Dual Agency where you or your brokerage represents both sides of the transaction. Limited info can be shared to either party. Both parties must agree and sign a one page agreement.
Sub-agency is not offered either brokerage that I have worked for. But the gist is I was with Broker A and did a one-time deal on behalf of Broker B. One close example: I closed a listing I had with my previous broker, after I had moved my license to current broker, but out of respect for my client I went to the closing with them.