There is no greater Reluctant protagonist than Bilbo Baggins in ‘The Hobbit’. He doesn’t really want to go on an adventure, but Gandalf nudges him out the door. Or in the film, he shakes himself down and runs out the door on his own, something he almost immediately reconsiders on realising he has forgotten his handkerchief.
Reluctant Protagonists are usually swept into the story by accident. You do have to be careful to not make reluctant Protagonists annoying. Fine, yes they might not want to be where they are, and they might find a lot of the things that are happening in the plot distasteful, but want they need to find is their purpose.
Eustace Scrubb in ‘The Chronicles of Narnia: Voyage of the Dawn Treader’, is another classic example of a reluctant character. He does eventually find his place, and then he finds himself as a main character in the next book. All that has to happen is that his greed turns him into a dragon.
Han Solo is more lucky; he gets his reward, gets to help blow up the Death Star, finds a better place in the universe and wins the heart of a beautiful Princess. He pays for his past mistakes, which is part of what made him a reluctant character in the first place, but he gets over that because he’s honourable and it is that honour that condemns him to be hunted by Boba Fett.
In many ways a reluctant protagonist is very similar to a naive protagonist. They might not be aware of the wider world around them and the events they are taking a part in, like Eustace Scrubb. But then again like Han Solo they might be more than aware of the dangers facing them. Such characters then become quite useful, because they might find different solutions to problems because they aren’t naive and are very experienced, like Han Solo who thinks very quickly on his feet.