A Customer Service Record (CSR) is the document of proof for a given phone number. Therefore, if you submit a CSR with your initial port request and ensure that the information on your LOA matches the information on the CSR, the likelihood that your port request proceeds without a hitch increases greatly. To ensure that your port request goes through as quickly as possible, you should provide a CSR with your port request whenever possible. While providing a CSR may require a little extra effort on the front end, it will likely save you time in the long run.