AT&T P506 User Manual page 4

If you are a new Pay As You Go customer,
see the Quick Start Guide for quick and
easy activation instructions.
If you are transferring service from another wireless carrier,
you may be able to keep your current phone number.
See Q&A on page 16 for details.
2
Attention:
If you are using this handset with
existing AT&T wireless service, you do
not need to activate a new account.
Simply charge the battery and move
your existing SIM to this handset.
1. Remove battery
cover and battery.
2. Insert existing SIM.