How do you make changes to mongod.conf after installing using charmed mongodb?

Installed mongodb using charmed mongodb. connecting from other nodes in the cluster works. but when i try to connect from external client from outside network connection is getting refused. looked at the config it shows mongdo db binding ip is diffarant. i need to change it to 0.0.0.0 to allow it connect from outside. i could not edit as it is readyonly, tried changing permission of file. stopping charmed mongdob service. still did not work. is there any command to change settings of mongod.conf after installing using charmed mongo db ??