All the user requirements, their division in iterations and the priorization have to be validate by the client/user. This validation is made with the signature of the client/user in the user requirements documentation.
The user requirements should be validated with the prototype. The team have to upgrade the prototype of the conception
phase to show the client a new version of the prototype where the client can see all their main user requirements, and
imagine in a more concrete way how the software will work when finished.
Steps
Update prototype to show all main user requirements.
Meet with the client to present and validate the user requirements with the updated prototype