Mass changing default password on Cisco 7940 phones

I am trying to mass update the admin password on a bunch of Cisco 7940 phones.

I am using end point manager which use SIP$mac.cnf file. I would like to change all of the passwords on these phones to something other than cisco, I see the following defined in the file but I don’t know where $telnet_password is defined. Could you let me know the best way to go about changing this please?

phone_password: “{$telnet_password}”

I would also like to change the logo on the phones and have the same question on the following line:

logo_url: “{$logo_url}”