Hi @Ozan Ozcan, welcome to the Atlassian Community!
For security reasons, we're unable to change the email address associated with your account. If the email address is from your previous company, your best bet is to contact your former employer to ask if they may be able to help you reclaim your account by temporarily activating your old email address. Once your old email address is activated, you can recover your password at https://id.atlassian.com/login/resetpassword.
You might also check if you’re still logged in to the account on one of your devices (for example, on your mobile phone) so that you can share access to your boards with your new email address.
Alternatively, you can feel free to create a new Trello account at any time. Many users maintain multiple accounts for work and personal use. If there were other members on your boards, you can reach out to them and ask them to add your new account to those boards.
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