Yes, if you would like to replace the free phone number associated with your trial account, you can by following these steps:
- Release your current number.
- Once you have released your current number, you can get a new number through the Buy a Number page.
You will not be billed for any numbers “purchased” during your free trial. The billing cycle for phone numbers and billing for usage will only begin once you upgrade your account. All Twilio services you used prior to the moment you upgrade are free.