So I took over a clients pastel accounts and the year end was set incorrectly as February instead of September. Pastel support says just change the no. of periods to 7 and then do the year end at the end of September. But when I do this I get the error " Changes made to the financial periods are not compatible with the Tax Manager"

Now I am stuck, any suggestions on how to change my year end to September would be greatly appreciated ! Data has been captured so I would like to continue using the current set of accounts instead of opening a new company on pastel.