I agree with the other posters that there are a LOT of different options that could be placed on a LO deal. There is no standard agreement, it all depends on the person who is selling and what they want.
My advise is to have a Real Estate lawyer, rather than an agent, be your adviser on this. A lawyer would be able to go through and understand all the verbage in the agreement as well as be able to advise on the proper way to change the agreement. Agents are more used to standard agreements and will probably need the help of a RE lawyer when deviating from the standard anyway. So you might as well skip that step and go straight to a lawyer, it will save you some money too.
Keep in mind that on a LO deal, EVERYTHING is negotiable. If you don't like something, either negotiate it to the way you like it or walk away from the deal. Agreements are always written to benefit the party that is writing it. So if the other party is writing the agreement, it will be geared to benefit them, not you. So make sure you read everything.
It CAN be a good deal and option for you, but you MUST, MUST, MUST read everything and do not take anything for granted. Also, if it is not written, it does not count. The law only recognizes Real Estate agreements that are written, nothing verbal counts.