Using the New Outlook for Mac for personal email and calendar
Hello Tom,
This 30-day delay is intentional. It’s a security safeguard designed to protect users in case someone else tries to hijack their account by changing recovery info. The wait gives the rightful owner time to notice and stop unauthorized changes.
Unfortunately, this policy cannot be bypassed. Microsoft doesn't grant their support staff any tools or access to help users bypass it manually either. I am sorry.
Microsoft's document explains it here.