Is there a cheat to lose republican tradition or become a monarchy/empire

[♱ Remilia Scarlet 🦇]

My country is a repubic and I want to become a monarchy or an empire

[Raven Frostborn]

Not that I'm aware of. If you're desperate just go to the EU4 wiki, it has a page that lists all the console commands in the game. It's pretty easy to lose tradition though, just keep electing the same person over and over, each election will lower your tradition.