what is post-convection relief?

Question

re--trial

Answer 1

I think you mean post conviction relief......
It is a proceeding where a criminal defendant may challenge a judgement of conviction which has already undergone appellate review and become final.
There is generally a time limit in which a motion for post-conviction relief can be made.

Answer 2

Post-conviction relief refers to the defendant's rights after sentencing. This may include modification of incarceration time, restitution, or other sentence requirements. It may also allow for the case to be re-tried.

Here is the definition according to Arizona Statutes. This may vary from state to state.

A.R.S. 13-4231.
Scope of post-conviction relief

Subject to the limitations of section 13-4232, any person who has been convicted of or sentenced for a criminal offense may, without payment of any fee, institute a proceeding to secure appropriate relief on any of the following grounds:

1. The conviction or the sentence was in violation of the Constitution of the United States or of this state.

2. The court was without jurisdiction to render judgment or to impose sentence.

3. The sentence imposed exceeded the maximum authorized by law or is otherwise not in accordance with the sentence authorized by law.

4. The person is being held in custody after his sentence has expired.

5. Newly discovered material facts probably exist and that the facts probably would have changed the verdict or sentence. Newly discovered material facts exist if:

(a) The newly discovered material facts were discovered after the trial.

(b) The defendant exercised due diligence in securing the newly discovered material facts.

(c) The newly discovered material facts are not merely cumulative or used solely for impeachment, unless the impeachment evidence substantially undermines testimony which was of critical significance at trial such that the evidence probably would have changed the verdict or sentence.

6. The defendant's failure to appeal from the judgment or sentence, or both, within the prescribed time was without fault on his part.

7. There has been a significant change in the law that if determined to apply to the defendant's case would probably overturn the defendant's conviction or sentence.