are you allowed to retrain a shaman spirit?

[Atalius]

for example, can you retrain a life spirit to a heaven spirit?

[Gallant Armor]

RAW I would say you can't (at least not directly). Spirits are equivalent to mysteries or patrons and the retraining rules don't allow for either to be retrained.

It's not an unreasonable thing for a GM to allow though as long as it's not being abused by a player planning retraining into their build.

Retraining all of your Shaman levels would be a way within the rules to pick a new spirit, although some GMs might require that you retrain all of your shaman levels to another class and then back to shaman.

[Lathiira]

Retraining rules per Ultimate Campaign allow the retraining of class features. Mind you, the shaman was released after UC, so we don't have a definitive answer. If you use the oracle as your basis for a decision, then I'd say Gallant is right. But by the rules...we got nothing.