A. The plaintiff is an autonomous management organization composed of occupants to manage the 727 generation and ancillary facilities located in Daegu-gu Dong-ro 489 (hereinafter "the apartment of this case"). The defendant is a company that operated gas facility construction business, etc. and received a contract for individual heating conversion work from the plaintiff, and the supplementary intervenor (hereinafter "the supplementary intervenor") is the defendant.

The defendant's worker is the defendant's worker who has worked at the construction site under a contract between the plaintiff and the defendant.

B. On June 5, 2012, the Plaintiff: (a) signed an agreement with the Defendant to modify the construction contract to modify the contract amount of the said construction contract, the payment method for the construction price, etc. on August 8, 2012, under the following terms, under which the Plaintiff contracts the Defendant for the conversion of individual heating units to the Defendant for the first unit of the sold co-ownership:

hereinafter referred to as "the construction of this case" and "the construction of this case"

1) Individual heating conversion contract: Sale 1: 2. The name of the first Bosco 1: the construction period of individual heating conversion works: From June 20, 2012 to September 20, 2012: 465,000 won (including value-added tax, 93,500,000 won for the first intermediate payment of KRW 139,50,000 for the second intermediate payment of KRW 93,500,000: 139,50,000 for the second end payment of KRW 2: 00,000 for the first end payment of KRW 3: 2: 00,000 for the first end payment of KRW 2: 00,000 for the first day: 00,000 for the first time: 00,000 won for the contract amount of 2/1,000 for the first time: 00,000 won for the change of contract: 06.