It's always possible to change your mind! Depending on whether you applied for the position with or without an account, you proceed in slightly different ways π
Applied without an account
If you've submitted your application without an account, you won't be able to withdraw your application yourself. What you need to do is simply to contact the employer and inform them that you're no longer interested.
Applied with an account
However, if you applied with an account, you have more control!
Start by logging into your account
From the main menu, press on the "Applications" button to access the list of all the applications you've sent/started
Find the application you want to withdraw in the list. On the far right, there's an arrow; this is what you press to withdraw the application from the recruitment
You'll still see the application in the list, but it will be marked as "Withdrawn by candidate".
The most common scenario is that the withdrawal can be done up until the last application day, but some employers have set it up to be possible until they conclude the recruitment process. If you don't see the arrow next to the application, it means it can't be withdrawn from the account, and then it's the employer who can assist you further!
Contact the employer
Depending on how far you've progressed in the recruitment process, and to avoid misunderstandings, it can also be courteous to contact the employer and explain why you've chosen to withdraw your application.