Has anyone had to hack into a server so they can set up their work,

Literally have a client asking me to do this change to their site and they are asking the dev who is controlling it but they just not letting me access ..

Long night ahead 🙄 got to add a ftp account ... All I need to do is add small lines of code for tracking, but this guy doesn't want to let me on it cause I'm slowly taking over his work... if he did his job right it's not like it would be happening anyway