I have a change MC who has some pretty big flaws (attitude). Because he is a change character, he will eventually alter his perspective and grow.
My question is, if the MC is the one the audience will see the story through and most identify with, do you think the audience will immediately reject him?
Just have them save a cat in the first couple of pages.
Yes, of course! Should make for an interesting opening 
I think ālikabilityā is frequently misunderstood, and overrated. We want people we are fascinated by.
Also, donāt forget that lots of people are disgusted by themselves, or at least corners of themselves, so they may find a lot to empathize with in a dislikable MC.
Edited: sympathize --> empathize
Hmm. Iād second what MWollaeger said; itās less about whether an MC is likeable, and more about whether heās interesting. Or rather, whether heās real. Real people are complex, filled with contradictory impulses and traits, especially when their minds have been wound tight around a problem they donāt know how to solve. Doing mean or cruel things doesnāt necessarily make your character unlikable. Think about the last time you abandoned a book because of an āunlikeableā MC. Was it because you found that character too mean, too cruel, too impolite, too full-of-himself? Or was it because you found him unsympathetic? Unrelatable? Boring?
If your MC is a prick, ask yourself: WHY is he this way? Can you telegraph this reason to the reader, even if you donāt spell it out entirely? People will tolerate a lot of bad behavior from a character if they can understand where that character is coming from. And as for whether your MC is likeable: do you like him? If so, what do you like about him? What are his most positive attributes? Is there any way you could give readers a hint of this stuff early on?
Yes, Mike hit it with likeability - itās such a vague term that, chances are, whoever is using it is doing so because they donāt know or canāt put their finger on specifics. Also, as Audz notes, the key is understanding their motivations and why theyāre doing what theyāre doing, even if we donāt agree with it. Empathy doesnāt mean to like, it means to understand. You donāt necessarily want a character to sympathize with (I think Mike meant empathize) because thereās a distancing factor going on (or as my mother would say, āI feel for you, I just canāt quite reach youā) with sympathy. Here is a good, short video on the differences.
If you can empathize, find them fascinating and give them positive attributes (how do other people see them?), then your well on your way.
This is actually something we all struggle with. We all want a flawed MC that either transforms when it is a āChangeā character or grows into his/her resolve when it is a āSteadfastā character. But it usually is not a good idea to start the story with an āangelā. But how much evil can they get away with before the audience starts to hate your MC? Why is Humbert Humbert (Lolita) more relatable than, say, Sid (Toy Story), while what Sid did, was objectively not that bad? This is a hard question to answer.
One of the keys is that their flaw should be something we can imagine can be a peeve or a temptation for someone. The hosophobia and OCD of Melvin Udall (As Good As It Gets) might be a good example of a relatable flawed character.
Some ideas to anchor the viewer with a relatively more empathetic character intro.
Make the first/intro scene the āwoundā from the backstory. Then time jump forward to present day. Example: Guardians of the Galaxy. Itās hard to unsee it now, but imagine starting with an obnoxious present day Peter Quill. He wouldnāt be as relatable compared to starting with, āIām a kid, my mom is dying, she wants to reach out, but I canāt process this, so I run away.ā Those few minutes are all you need to hang in there while present day Peter is acting a fool.
Make the first/intro scene a fragile scene from later in the movie. Then time jump back to present day. Example: Michael Clayton. Heās hassled during poker, dumped on by an obnoxious client, and almost blown up. This is before the viewer learns about, āheās defending unscrupulous people and relatively OK with it.ā
My wife and I watched 1922 on Netflix a week or two ago. She asked of the main character, āAre we supposed to like this guy?ā I was like, āOf course not,ā but she said, āI think we are. Heās not a good guy, he did a terrible thing, but I think weāre supposed to like him.ā Though I did not like him, I did not ārejectā him, but neither did I root for him to get what he wanted. I think this conversation nailed it. I understood his plight and wanted to see how he handled the problem in spite of disliking him because he was a good character though not a good person. He felt real because he was flawed.
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I thought I would mention that unlikable main characters/protagonists have a long literary history. I wouldnāt worry about audience reception just because they may be unlikable at first. Some examples of (initially) unlikable characters from cinema include:
Gru, Despicable Me (cheater, thief, fraud)
Alex, A Clockwork Orange (violent)
Peter Banning, Hook (selfish, concerned with wealth)
Riddick, Pitch Black (violent criminal)
Shrek, Shrek (selfish, anti-social)
Lightning McQueen, Cars (vain, selfish)
Wikus, District 9 (prejudiced)
Jason Nesmith, Galaxy Quest (vain, resentful)
Jill, Butterflies Are Free (shallow)
Joe, Some Like It Hot (fast-talking schemer)
In most cases their rough edges get smoothed, and weāre willing to wait out the process. At other times you want an unlikable MC who remains unpleasant (Riddick is unrepentantly steadfast, but his violent nature is the only reason why some of the crash survivors escape).
So this is a bit off topic. Oh well.
My favorite Save the Cat moment is in The Incredibles when Mr. Incredible isā¦well, saving a cat. It seems a bit silly to need to be reminded that the superhero in a superhero movie is the good guy and thus seems like theyāre making fun of STC a little bit. Donāt know if iām the only one that takes it that way. But the real beauty of it is this. While all the Save the Catters can watch that movie and say āsee we told you, you need to save a cat!ā all the Dramatica-ers know that the real meat in that moment is how saving a cat is problematic for Mr. Incredible. Mainly in that, while heās trying to get the cat out of the tree, the bad guy is getting away and the longer the cat holds on the more time to stop the bad guy runs out.
Check out the āNegative Trait Thesaurusā & the āEmotional Wound Thesaurus.ā