In some cases, if a party is unhappy with an order or decision, the correct route is to appeal the decision.
In others, there needs to be an application made to set aside or vary the order. The most common instance is where an order is made without a hearing (and so without the parties present): in such cases the order will give the parties liberty to apply, normally within 7 days.
In these cases, and where the order is silent on liberty to apply, the relevant provision is CPR r 3.1(7) which provides that:
“A power of the court under these Rules to make an order includes a power to vary or revoke the order.”
However, the application of r 3.1(7) is constrained by the guidance set out in Tibbles v SIG (trading as Asphaltic Roofing Supplies)  EWCA Civ 518,  1 WLR 2591 (Bailii link here). As a rule, the discretion can only be exercised where there has been a material change of circumstances since the original order was made; where the facts on which the original decision had been made were (innocently or otherwise) misstated; or where there had been a manifest mistake on the part of the judge in the formulation of the order. Where liberty to apply is expressly provided, of course, the discretion will not be so fettered.
The logic underpinning the decision in Tibbles is straightforward: there is a public interest in the finality of litigation, and it is undesirable to allow litigants the opportunity to have two bites of the cherry. By a similar token, it is important not to undermine the concept of appeal: the jurisdiction afforded by CPR r 3.1(7) therefore needs to be restricted so that it does not overlap with appeals.
In Tibbles Rix LJ set out some more guidance at para 39. It ought, he commented, “normally to take something out of the ordinary to lead to variation or revocation of an order, especially in the absence of a change of circumstances in an interlocutory situation.”
Plausibly, the manner in which r 3.1(7) should be applies will vary according to context. So, for instance, when dealing with interim injunctions it will be relevant that the interim injunction is a “non-procedural but continuing order which may call for revocation or variation as it continue[s]” – Roult v North West Strategic Health Authority  1 WLR 487 at  per Hughes LJ, obiter, cited in Tibbles at .
We know that orders can be set aside on the grounds that they were made on a mistaken basis – Edwards v Golding  EWCA Civ 416 per Buxton LJ. But it appears that the jurisdiction under r 3.1(7) can arise even if the grounds which are relied upon could have been known to the applicant before the order in dispute was made or agreed (although there will likely be a consequential order in costs) – c.f. W L Gore & Associates GmBH v Geox Space  EWCA Civ 622 per Lord Neuberger at . And, it would seem, even in context of “pure” legal argument – i.e. where one party has missed a fundamental legal point (Edwards again).
What of the need for promptness? Well, there is high authority suggesting that any application under r 3.1(7) must be made promptly: Thevarajah (Respondent) v Riordan and ors (Appellants)  UKSC 78 (available on the UKSC website here), citing Tibbles at para 39(ii).
I am inclined to think that the reference to “prompt[ness]” in Tibbles at  may be directed at the situation where there is an error “on the materials already before the court” – and there is some support for this from the Court of Appeal (Michael Wilson & Partners Ltd v Sinclair  EWCA Civ 774,  C P Rep 45 per Richards LJ at , where Richards LJ states that it is “in that context [i.e. the context of an application back to a court to deal with a matter which ought to have been dealt with but which in genuine error was overlooked] that he [Rix LJ in Tibbles] emphasised the word “prompt” . . .]”
But this isn’t an altogether attractive argument, and I would anticipate that any court will take Riordan at face value on this point – particularly since r 3.1(7) is so close (physically and metaphorically) to r 3.9. Promptness, therefore, is important.
In short, where a party is unhappy with an order, they should bear in mind that the general power to revoke and/or vary orders under r 3.1(7) is fairly well circumscribed: if an appeal is available, then appeal is likely the correct route; the party will need to show a material change in circumstance since the order was made, or misstatement of the factual basis for the order, or “manifest error” in the making of the order; and any application to court must be made promptly.
(parenthetically – the Supreme Court in Riordan emphasised that, where a court has made an interlocutory order, it isn’t normally open to a party subsequently to ask for relief which requires that order to be varied or rescinded, save if there has been a material change in circumstances since the order was made (or if, in terms, new facts have come to light); where a party is fixed with an interim injunction, and not happy with it, the best route might be to apply for directions for an expedited trial, rather than for variation and/or discharge of the order, absent any material change in circumstance).