Why am I unable to use “Change Voucher Type (Alt + F11)” in sale screen after entering data?

Solution:

The “Change Voucher Type” will work only with the blank vouchers. You have to select the voucher type before creating the voucher. Since the voucher type controls all the options of a transaction, it is not possible to change that after entering data.

For more details, please visit: http://www.rancelab.com/help/fr6_voucher_type.htm