And if it is possible, how do you prevent other people from claiming they are you and lost their phone?
Amazon only directs you to a page which does not exist. http://aws.amazon.com/iam/faqs/
If the authentication device associated with the AWS account is damaged, lost, stolen, or stops working, you will need to contact us (http://aws.amazon.com/foms/aws-mfa-support/) for help with disabling AWS MFA for the account. This will allow you to temporarily sign in to AWS using just the user name and password for the AWS account.