Nope. The consensus is very clearly defined. Users of coins have absolutely nothing to decide in this decision making process. If you want to understand how Bitcoin works I would suggest to study the whitepaper. If a switch to another algorithm would be possible, bitcoins would be worthless bits. The most important feature of the network is that some elements can't change, first and foremost the money supply and proof-of-work. You can ask some of the miners and core developers how likely such a switch is.