An ______ occurs when any condition or document modifies the work as defined in the contract during the bidding process.

An addendum is a document that modifies the original contract terms and is used to clarify or change conditions before the bidding process is completed. It serves to inform all potential bidders of any alterations or additional information that may impact their bids. By issuing an addendum, the owner or project manager ensures that all bidders are aware of the updated information equally, thus maintaining fairness in the bidding process.

In contrast, a change order typically occurs after a contract has been awarded and involves changes made to the work scope, schedule, or costs after construction has begun. A request for information (RFI) is a formal inquiry raised by a contractor seeking clarification on contract documents but does not modify any terms. Finally, a proposal is a formal offer submitted by a contractor to perform specified work at a certain price but does not inherently change the contract terms during the bidding phase. Thus, the addendum is the appropriate choice for modifications made during the bidding process.