Is there a way to have the currency of a supplier changed or to batch change the expenses assigined to a projects from one supplier to another?

Hey there, finance127.

I can share some information regarding changing the assigned projects or a supplier's currency in QuickBooks Online.

The option to change by batch for the assigned projects from one supplier to another or changing the supplier's currency is currently unavailable in QuickBooks Online.

As a workaround, you can make the supplier inactive. After inactivating, you can add them again with a slightly different name and choose the new currency.

To add a supplier, here's how:

1. Select Expenses, then Suppliers.
2. Select New Supplier.
3. Complete the fields in the Supplier Information window.
4. Choose the new currency.
5. Select Save and close

Once done, you can open each assigned project and manually change the supplier. This way, it helps you ensure their balances are accurate in QuickBooks Online (QBO).

Furthermore, I recommend visiting this website: Multi-currency Overview. It has in-depth details about the effects of using the Multi-currency feature on your company's accounts and balances. It also provides you links to learn more about this functionality in QBO. 

I'm just a comment away if you need anything else. Enjoy the rest of your day!