Conn. Gen. Stat. § 52-128: Amendment of pleadings by plaintiff; costs.

The plaintiff may amend any defect, mistake or informality in the writ, complaint, declaration or petition, and insert new counts in the complaint or declaration, which might have been originally inserted therein, without costs, within the first thirty days after the return day and at any time afterwards on the payment of costs at the discretion of the court; but, after any such amendment, the defendant shall have a reasonable time to answer the same.