1. The plaintiff's appeal and the defendant's appeal are all dismissed.

2. The portion resulting from the participation in the appeal costs.

1. As to the instant case cited in the judgment of the court of first instance, the reasoning of this court is as stated in the reasoning of the judgment of the court of first instance, except for partial dismissal, addition, or deletion as follows. Therefore, it is acceptable in accordance with the main sentence of Article 420 of the Civil Procedure Act.

Of the fifth page of the judgment of the court of first instance, the term "from March 12, 2012 to September 30, 2013" is "from March 12, 2012 to September 30, 2013" as "from April 25, 2012 to September 30, 2013."

In Part 7 of the decision of the first instance court, the defendant shall add "the provisions related to the respective terms and conditions of guarantee" to the following in Part 3 of the decision of the third instance.

The following shall be added between the 7th sentence of the first instance and the 6th sentence:

“2) On October 30, 2012, the Defendant concluded a modified contract with the Plaintiff and C to change the contract amount to KRW 21,980,200 on October 26, 2012 as of October 26, 2012, and the contract amount to be changed to KRW 21,980,200,00. The modified contract is an ordinary contract which finally terminates the former obligation under the existing subcontract and establishes a new obligation. Since C fully performs its obligations under the said modified contract, it asserts that the Plaintiff’s expression of intent to terminate the instant subcontract with C on October 31, 2012 is null and void.

As to the instant construction work on October 30, 2012, the Plaintiff and C prepared a written subcontract to alter the content that the date of completion is earlier than October 26, 2012; the contract amount is reduced to KRW 21,980,200,000; and C, on November 6, 2012, may be recognized as either the principal contract amount of KRW 21,980,200,000 on the said modified subcontract agreement from the Defendant, as the principal contract amount, and the date of completion as of October 26, 2012, submitted to the Plaintiff by obtaining a warranty bond stating the date of completion as of October 26, 2012, either there is no dispute between the parties, or the purport of the entire pleadings as stipulated in subparagraphs 1 and 2.

However, the novation under Article 500 of the Civil Code is a contract to change the important part of the existing obligation to extinguish the existing obligation and to establish a new obligation without identity.