How do I allow suppliers to change advanced pricing details on order confirmation line items?

You must enable the transaction rule Allow suppliers to change advanced pricing details on order confirmations at the line-item level in your SAP Business Network account.

If this rule is enabled, suppliers can change price unit quantity, price unit, unit conversion, and pricing description for a line item on order confirmations. This rule does not apply to scheduling agreement and scheduling agreement release confirmation.

SAP Business Network for Procurement & Supply Chain > Administration (Buyer & Supplier Account Administration)