Usually, no. An appeal is based on the record created in the lower court or agency proceeding. The appellate court reviews transcripts, motions, rulings and admitted evidence to decide whether a legal error occurred. It does not hear new testimony or consider evidence that was never made part of the record. That is why trial-level decisions and objections often matter so much on appeal.

Winning an appeal does not always mean you immediately get the final result you wanted. In some cases, the appellate court reverses the lower court and enters a ruling that directly changes the outcome. In many other cases, the court sends the matter back for more proceedings consistent with its opinion. That may lead to a new hearing, a new trial or another decision by the lower court using the correct legal standard.
Usually, a settlement limits appeal rights because both sides have agreed to resolve the case. A guilty plea can also limit what a defendant may challenge later, though some issues may still remain open in certain situations.

The answer depends on the exact terms of the settlement, the type of plea and the issue you want to raise. A careful review of the record and final documents is the best way to tell whether an appeal or another form of post-judgment relief may still be available.

Missing the appeal deadline can be fatal to the case. In many appeals, courts enforce filing deadlines strictly and will dismiss a late appeal even if the underlying issues are serious. That means the lower court’s decision usually stays in place. Because the clock often starts running as soon as the judgment or appealable order is entered, it is important to speak with an attorney as soon as possible.
If the appellate court agrees that the lower court made a harmful legal error, it may reverse the decision, remand the case or do both. A reversal means the appellate court changed the lower court’s ruling because of that error. A remand means the case goes back to the lower court for more action, often under instructions from the appellate court. In some cases, the appellate court may also modify part of the judgment without requiring a full new trial.