25 CFR §23.115

1. (a)Either parent, the Indian custodian, or the Indian child's Tribe may request, at any time, orally on the record or in writing, that the State court transfer a foster-care or termination-of-parental-rights proceeding to the jurisdiction of the child's Tribe.
2. (b)The right to request a transfer is available at any stage in each foster-care or termination-of-parental-rights proceeding.