Yes.
Either when you cave in to an event (goes away for 10 years) or when you modernize your military (permanently removes it).
In general you want to give in to an event, regain your stab, centralise fully (if needed) and then modernise when the remove western influences expires. Ideally you do this after westernising all the way to Latin so you only have to take the -6 stab and other penalties for modernization once but you can do it at each stage of westernising.
Going republican when Westernizing is a pretty good idea.