Why will it not let me change my home currency?

It's my pleasure to welcome you here in the Community forum. Thanks for reaching out to us. I'd be delighted to provide details about the home currency in QuickBooks Online.

Once you've already set up or activated the Multicurrency feature in QuickBooks Online, you're unable to change it in QuickBooks Online. 

You can only change the home currency by deleting all your data and starting over from scratch. Here's how:

1. Cancel your current company.
2. Start a new company.

You can also check this article for more details on how to turn on and use multicurrency.

If you have further questions, feel free to click the reply button below. I'm always looking forward to helping you in the future. Take care!

@banking-yourrent 

Another option, purchase a 3rd party service to convert your data to a new home currency.