The government and contractor teams are co-located in the same office. The govt program manager (PM) wants to move up the date for a major deliverable by a month to satisfy a customer request and is willing to change the deliverable's requirements from what is defined in the contract to help make this happen. What is the appropriate way to authorize and coordinate this modification with the contractor?

1) Through a formal contract modification

2) By documenting the request in an email

3) Through a requirements modification meeting