Hi,

As per your query,to be able to use different Price list in the same session, we can do so by following the below steps:-

1) First we need to enable multi currency functionality to the selected user by following Setting >Users>Users

2) Once we do so, we need to also set the Secondary Currency of the Default Debit Account and Default Credit Account same as that of the Currency of the Payment method,(i.e. if we want the payment method to be set in USD, then we also need to configure Secondary Currency of the respective account as mentioned above to USD). This can be done through Accounting>Configuration>Accounts

3) Then we need to change the currency in Payment Methods, (i.e. select the currency type configured for the debit and credit accounts).This can be done by following Point Of Sale>Configuration>Payment Method>Currency

In this way multiple price list can be maintained in same session in POS.

Hope it helps.

Cheers!!