[Karunamon]

No, but changing the constitution is not a minor affair. You can't just propose one amendment through the legislative process, you have to launch a convention, and the country you get on the other side of that may not have much in common with the country now.

[Amezarak]

You certainly can change the Constitution without a convention. The federal legislature passes it with a 2/3rds vote and then the states ratify it.