Rinoa is the only character with two Limit Breaks. Her regular one, Combine, summons her pet dog, Angelo. Her second one, Angel Wing, is not available until Disc 3.

Combine
Combine is a weirdly-named limit break that is really just the summoning of Angelo, who can learn pet tricks from the Pet Pals magazines that are found or bought in various places around the world. His appearance happens automatically, with a random trick pulled from the list.

Once you read about a trick from Pet Pals, you must train Angelo for it by selecting it in Rinoa's status menu. Everytime she walks around (and yes, she must be in your party for this) the trick's bar will steadily fill up. When it's full, you will hear a distinct chime that indicates that the trick has been learned and is now available for the limit. The following is a list of tricks that Angelo has at his disposal.

Pet Pals Vol. 1 can be found on the train to Timber. Vol. 2 can be found on Rinoa's bed in the train. Vols. 3 and 4 can be bought at the Pet Shop in Timber for 1000 gil each. Vols. 5 and 6 can be bought at the Pet Shop in Esthar for 1000 gil each. If you missed finding Vols. 1 or 2 in the beginning of the game, you can also buy them at Esthar.

Angel Wing
This limit break is gained only in Disc 3. You don't have to do anything for it; Rinoa knows it automatically. Now, whenever a limit break is available in battle, you can choose to either select Combine or Angel Wing.

It's really nothing else than a Berserk-like status, but Rinoa casts random spells without using her spell inventory. While this is potentially useful, many spells that are cast are random (without strategy at all) and may even be useless. So far, we don't know if Rinoa can use "special" magic like with Selphie's limit.