What is a common way a procuring employee might engage in a bid manipulation scheme?

A procuring employee can engage in a bid manipulation scheme through various unethical practices, all of which contribute to corrupting the competitive bidding process.

Opening bids prematurely can give the employee undue advantage by allowing them to see competitors' proposals before they submit their own. This action compromises the integrity of the bidding process, since all bidders should have an equal opportunity to present their bids without influence from others.

Extending bid opening dates without justification disrupts the timeline of the bidding process and may mislead or manipulate bidders. This can allow a procuring employee to either give favored vendors more time to prepare their offers or even adjust their proposals after seeing initial bids from competitors.

Altering bids is a direct form of manipulation where the procuring employee changes the values or terms of submitted bids, potentially favoring a particular vendor. This fraudulent act skews the competition and can lead to the selection of a vendor based on manipulated criteria rather than the most qualified or cost-effective option.

Since all the provided actions are common tactics used in bid manipulation schemes, the comprehensive answer encapsulating these unethical practices is indeed ‘All of the above,’ reflecting the various methods through which a procuring employee can influence the bidding process to achieve a desired outcome, often for personal benefit.