Generally, the winning contract cannot be signed by the branch. After the head office won the bid, the contract signed by the branch company and the tenderer did not conform to the provisions of the Bidding Law. The tenderer and the winning bidder shall conclude a written contract in accordance with the tender documents and the bid documents of the winning bidder within 30 days from the date of issuance of the bid-winning notice, and the final contractor shall be the winning bidder. If you win the bid in the name of a branch, that's another matter.
legal ground
Article 46 of the Bidding Law
The tenderer and the winning bidder shall, within 30 days from the date of issuance of the bid-winning notice, conclude a written contract in accordance with the tender documents and the bid documents of the winning bidder. The tenderer and the winning bidder shall not conclude other agreements that deviate from the substantive contents of the contract.