Hello Melissa,
Thanks for your question.
If you mean you signed in to the wrong directory, you can simply just change directory. Click the settings icon and select the correct one.
However, Once an Azure account is associated with a tenant, you cannot directly change the organization it is linked to.
If this is the case, I would recommend you try and contact support for further steps: https://support.microsoft.com/en-us/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola