Is it possible to updated the Merger Key for App Channel List

Hi Experts,

We have a customer who recently live, and after few days it was noticed that the Merger Key for a App Channel List was supposed to be MOBILE_NUMBER_ but while creation it was selected as CUSTOMER_ID_ so would like know if there is an option to update this key or please help us to know how to update the merge key and what is the impact on current data or any alternate approach to address this issue.