Updating SIP address

We have a new SIP provider. How do I update the SIP provider using Asterisk.

Do I just need to change it in the Asterisk config files, or do I have to change it on the HardPhones too?

Cheers,

Normally just in Asterisk, however it is theoretically possible, if unlikely, that your dialplan has been written to require changes in the phone.

You may need to change other information in sip.conf and extensions.conf.