Managing personal Outlook.com account settings, security, and privacy
Hey there! Nice to meet you!
Unfortunately, it is not possible to cancel the security info change request since you do not have access to the current verification method (your old phone number) linked to your account.
Your only option is to wait for the 30-day restriction state in order to fully update your security info and regain access to your account.
You may check this link for more information regarding the 30-day security info change:
Please feel free to let me know if you need anything else.
Best regards,
Darhyl