Replace config.boot

Hi,
I want replace file config.boot oin /conffig by one file other.
But i can’t replace because I haven’t permision.
How can i do that.
Thank

Hi, use sudo, but better to use command load /config/path

Thank, you can give me example

From configuration mode

vyos@R1:~$ configure 
vyos@R1# load /opt/vyatta/etc/config.boot.default
Loading configuration from '/opt/vyatta/etc/config.boot.default'
Load complete. Use 'commit' to make changes effective.
[edit]
vyos@R1# commit