Correcting future dates in Prorate dates calendar

Hello,

We added more records for future period (2022 and more....) to the prorata conventions calendar (FA_CONVENTIONS table).

However, some dates added are wrong.   The 2 last records are wrong.

Those periods are not used yet for any asset. It is for projection calculation purposes.

We tried to delete as mentionned in Note How to change the FA Fiscal Calendar to match the new GL Calendar? (Doc ID 1380156.1).

We get OFA-48169.   We cannot create a new calendar.

Is anybody has a script or how can we handle?

We are (11.5.10.2)

Thanks!