FALSELY ALTERS

A person "falsely alters" a written instrument when

(he/she), without the authority of anyone entitled to grant it, changes a written instrument, whether it be in complete or incomplete form, by means of erasure, obliteration, deletion, insertion of new matter, transposition of matter, or in any other manner, so that such instrument in its thus altered form appears or purports to be in all respects an authentic creation of or fully authorized by its ostensible maker or drawer; or
(he/she) signs (his/her) own name to a written instrument, thereby falsely and fraudulently representing that (he/she) has authority to sign the instrument.

Source: General Statutes § 53a-137 (6) (applies to Part X: Forgery and Related Offenses, §§ 53a-138 -- 53a-145).