I call two days ago asking the capital loss question in my tax return and agent say someone will reply to me in email but i still not receive the email

[ymwed3838]

I file my tax in 2024 in Cra but I forgot to put unused net capital loss in other year in line 25300 but I w as my to adjust my tax return in Cra account do , I have capital gain$2400 2024, but my Notice of assessment 2023 unused capital loss $15729 so what new amount I need to change in line 25300 in Cra ,please give me advice