Redemption from Excommunication?

[distortiondave]

If a loyalist chapter is excommunicated, is there ever a way back for them?
I know certain chapters are on penitent crusades, but they were never excommunicated.

If it transpired the Inquisitor responsible for declaring a chapter excommunicated was himself corrupted by chaos, and the reason for the chapter being excommuncated was discovered to be false, could they be unexcommunicated?

[librisrouge]

I would say that it depends on the conditions of the excommunication. If the person that did the excommunication was proven false then they MAY be forgiven their actions (especially if they didn't act against the Imperium during their time excommunicated.) Also, if they can get a political campaign mounted against their accuser they may be able to get him overridden by the High Lords of Terra or the Inquisition. Finally, if something happens that makes it blatantly obvious that the Emperor hasn't forsaken them they may be forgiven. This would be very rare but possible in theory.

Again, all this probably depends on two other factors:
1) Did they survive the excommunication. Most chapters are wiped out within days of them being informed of their excommunication.
2) How much did they turn away from the Imperium to survive it's wrath? Wiping the floor with Grey Knights may have been what you needed to do to survive but it doesn't endear you to anyone.

[matus]

I'd guess probably not. Like Librisrouge said, there a good chance they'll already be dead. Also the Imperium never struck me as an organization big on admitting that it was wrong or being to bothered about the suffering of innocents. They would probably see it as more dangerous to admit to the fallibility of the inquisition and most likely quietly execute the inquisitor, bury the whole incident under a mountain of administration and finish of any of the marines just to be sure. Lastly a lot of falsely accused chapters (well back in the heresy anyway) seem to turn to chaos in the end as a result of the accusation.

[Intrepid]

Yes, it is possible, but usually in the sense of "let my death prove my loyalty". The Imperium being more focused on dogma than practical results, they would need a reason to grant it in a way that lets the accused still go free. Bear in mind that Inquisitors can't freely pronounce Excommunication on just anyone--they need a good reason (with Marines a VERY good reason), just as an Inquisitor can't go around killing planets for giggles. Most fallen Inquisitors are more focused on things like using Chaos against itself or on believing psykers are the future of humanity rather than on killing sprees. The few exceptions (like Inquisitor Valinov of "Grey Knights") are quickly identified by their fellows and hunted with extreme prejudice.