Do you mean that when you re-enable the Audio Conferencing license, the service numbers for your conferencing bridge is changed?
You could try to update existing meeting invites of users of the Meeting Migration Service.
For more details, please refer to: https://video2.skills-academy.com/en-us/microsoftteams/change-the-phone-numbers-on-your-audio-conferencing-bridge#step-4---update-existing-meeting-invites-of-users-using-the-meeting-migration-service-optional.
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