In case you received a booking last year, but the sailing period is in this year, but the VAT rate changed between booking date and sailing date you can normally issue the final invoice that will reflect this.
For example, booking was created and confirmed on 05.12.2013. (1.), its sailing period is in 2014 (2.) and VAT rate at the time was 10%.
In addition you have received the first payment while the VAT rate was 10% and you have issued an Advanced payment invoice with the tax breakdown for 10% (1.).
But at the turn of the year the VAT rate changed from 10% to 13% so your second payment and the final invoice will have to comply to the new tax rate since you are issuing them after the VAT change.Your first step is to change the VAT on the calculation. Enter the new tax value (1.) and press Apply (2.).
When you have changed the Tax you can enter the second payment which will now have the 13% tax breakdown (1.).
Important thing is to change the tax rate before you enter the second payment.
With payments complete you can issue the final invoice, the invoice will have the correct tax rate of 13% (1.), but will show the correct tax breakdown for first payment with 10% VAT (2.) and for second payment with 13% VAT (3.)
Correcting the VAT on paymentIf you did not change the VAT on calculation, but you have entered the second payment while the tax was set to 10% and changed the tax rate to 13% after that, the advanced payment invoice will still show 10%.
The reason is that the payment gets the tax which is valid at the time of entering the payment and that will not change if the tax changes subsequently.
Simplest way to correct that is to delete the payment and enter it again under correct tax rate in calculation.
If that is not an option, then go to Payments, double click on Value of the payment to enter the field. Enter value 0 and press Enter to confirm.
This will reset the value and the tax for the payment. Now double click on Value of the payment to enter the field again and enter value the correct value and you will have the correct VAT on the payment.
If you need to correct the first payment change the tax on calculation first and apply, then repeat the process for the first payment and be sure to remember the change the tax on the calculation back.