Hi there, info-ceramitique.
You still have the option to change your Home Currency if you haven't turned on Multicurrency yet. If so, the system doesn't allow you to edit the home currency anymore as part of the agreement when you first turned the option on. This avoids messing up your sales tax reporting and books.
If you haven't turned on multicurrency, here's how you can change the home currency:
For more details on how to manage your currencies and frequently asked questions about multicurrency, you can refer to these resources:
Feel free to mention me if you need more help. Take care!