I'm not sure what you mean with the question. If you have any alias like alias rm='ls -l' in your .bashrc in example, then you cannot use the original command rm anymore, as it is aliased to something else. I'm speaking about the terminal, when you enter the command. However, if you put a backslash in front of it like \rm in the terminal, then the alias for it is ignored and the original command is executed instead.
Edit: Made a more clear alias example.