Annulation of protection can be done in the Czech Republic or at a Czech Embassy abroad. The annulation is made while waiting on the spot, free of charge, after filling in the application form (in duplicate). It is necessary to submit relevant personal documents (passport, etc.). The application must be submitted in person, for minors (up to 18 years of age) the parents must submit the application.

To present the aforementioned application at the Consular Section of the CZ Embassy in Riga, it is necessary to make an appointment - see the general procedure for performing consular acts at the Consular Section

https://www.mzv.cz/riga/en/consular_information/index.html

Comprehensive information about the mentioned issue is available on the web page of the Ministry of the Interior of the Czech Republic:

https://www.mvcr.cz/mvcren/article/information-for-ukrainian-citizens.aspx