A confidence vote is taken at the end of PI Planning after dependencies are resolved...

According to the SAFe Agilist 6.0 domain of PI Planning, the confidence vote is a process where:

Each team conducts a vote using their fingers (fist of five) or a digital tool for remote events

The teams vote on the confidence level for the objectives as a set, and if confidence is high enough, the aggregate set of objectives becomes the committed ART plan

The Release Train Engineer summarizes the team objectives into the ART PI objectives in a format suitable for management communication

https://scaledagileframework.com/pi-planning/