Alteration of the Constitution

Article 147
A motion to alter or supplement the Constitution of the Republic of Lithuania may be submitted to the Seimas by a group of not less than 1/4 of all the Members of the Seimas or not less than by 300,000 voters.
During a state of emergency or martial law, the Constitution may not be amended.

Article 148
The provision of Article 1 of the Constitution “the State of Lithuania shall be an independent democratic republic” may only be altered by referendum if not less than 3/4 of the citizens of Lithuania with the electoral right vote in favour thereof.
The provisions of the First Chapter “The State of Lithuania” and the Fourteenth Chapter “Alteration of the Constitution” may be altered only by referendum.
Amendments of the Constitution concerning other chapters of the Constitution must be considered and voted at the Seimas twice. There must be a break of not less than three months between the votes. A draft law on the alteration of the Constitution shall be deemed adopted by the Seimas if, during each of the votes, not less than 2/3 of all the Members of the Seimas vote in favour thereof.
An amendment of the Constitution which has not been adopted may be submitted to the Seimas for reconsideration not earlier than after one year.

Article 149
The President of the Republic shall sign the adopted law on the alteration of the Constitution and officially promulgate it within five days.
If the President of the Republic does not sign and promulgate such a law within the specified time, this law shall come into force when the Speaker of the Seimas signs and promulgates it.
The law on the alteration of the Constitution shall come into force not earlier than one month after its adoption.