I’ve added/edited Review Policies. Will those changes take effect immediately?

They will apply to all future transactions, but not previous ones. Whatever policies are in place at the moment a transaction is “marked for review” - the moment that the transaction is settled - will dictate what’s required. If the policy that is applied changes (ie. you create a new policy for a specific team) OR if the policy itself changes, any existing transactions won’t experience a change to their Review requirements.

Example A: On Monday, a transaction was made for $50 of AWS credits. The transaction had the Engineering team applied to it at the time the transaction settled. At that moment, there were two policies - once for transactions attached to the Product team, and the Default Policy for all other transactions. On Tuesday, a new policy was created for transactions attached to the Engineering team. The $50 AWS transaction from Monday will still be routed based on the logic of the Default Policy. On Wednesday, another transaction was made for $65 of AWS credits. The transaction had the Engineering team applied to it at the time the transaction settled. At that moment, there were three policies - one for transactions attached to the Product team, one for transactions attached to the Engineering team, and the default Policy for all other transactions. This $65 AWS transaction from Wednesday will be routed based on the logic of the Engineering Policy.

Example B: When the Engineering policy was created on Tuesday, it required all transactions above $0 to be reviewed by the Head of Engineering. On Thursday, the Engineering policy was edited to require all transactions above $500 to be reviewed by the Head of Engineering, and anything below $500 didn’t need to be reviewed at all. The $65 AWS transaction from Wednesday will still require the Head of Engineering to review the transaction, as per the original Engineering Policy rules.