Pathfinder: Swashbuckler; Opportune Parry and Riposte (Ex):

[Scottlang]

I have a character who is playing a swashbuckler.

The question is; the Opportune Parry and Riposte, if a character does not have Combat Reflexes; how many times could they use this action??

This is the wording of the ability:
Opportune Parry and Riposte (Ex): At 1st level, when an opponent makes a melee attack against the swashbuckler, she can spend 1 panache point and expend a use of an attack of opportunity to attempt to parry that attack. The swashbuckler makes an attack roll as if she were making an attack of opportunity; for each size category the attacking creature is larger than the swashbuckler, the swashbuckler takes a –2 penalty on this roll. If her result is greater than the attacking creature’s result, the creature’s attack automatically misses. The swashbuckler must declare the use of this ability after the creature’s attack is announced, but before its attack roll is made. Upon performing a successful parry and if she has at least 1 panache point, the swashbuckler can as an immediate action make an attack against the creature whose attack she parried, provided that creature is within her reach. This deed’s cost cannot be reduced by any ability or effect that reduces the number of panache points a deed costs.

I am not sure exactly how it works, and it does seem that he does parry and riposte more than he should. Could someone please help me with a ruling, before I tell my player what the thought is behind it.

[TheFamilarRaven]

Without a source of additional attacks of opportunity per round (such as the Combat Reflexes feat), the swashbuckler can only use this deed once per round. In addition, if they made an AoO earlier that round, they cannot use this ability.

An Immediate action consumes the swift action of the character's next turn (if the action was performed outside of your turn in the initiative order), but otherwise does not use up any more AoOs. They can only make the riposte attack if they still have panache points remaining, and haven't used any other immediate actions out of turn order.

[Rynjin]

Yep, just once. You "expend a use of an Attack of Opportunity" If you only have one of something, and expend it, you now have zero. You can't expend something you don't have.

Likewise, you only get one Immediate per turn, and it eats your next turn's Swift (though not bice versa; he could use a Swift on his turn and then use an Immediate off his turn the same round).

This means that even if you have Combat Reflexes, and let's say 5 AoOs, you could PARRY 5 attacks, but still only RIPOSTE a single attack; you can never Riposte more than once, since you only ever get a single Immediate.