We have a lot of issues creating SOs in the correct currency. The AR team detects the wrong currency once they invoice gets send to the customer. Is it possible to change the currency on the sales order once created and saved? Or is the only way to create a new SO with the correct currency?

No, not possible I'm afraid. Agree that deleting and starting again with the correct currency is the neatest way.

Make sure all the currency types are not available to customer records unless you are selling them in multiple currency

Alright, thank you guys!