Won't cooperate with you
Before You Begin
Pause and breathe. Even if this shouldn't be happening... accept that it is and embrace it with composure and calmness.
Calmness is the only way forward because without calm, there is no possibility for receptiveness and connection. Your child won't give to you any more than they see from you.
Never forget that a strong connection is fundamental, as there will be no correction in them if there is no connection with you.
The Core Problem
They don't feel a strong connection and/or cared about, so they are willing to enter a power struggle to show that you don't have control over them.
What Will Make It Worse
Forcing the child to cooperate or using negative consequences for their behavior will not help the situation.
Criticizing or shaming the child for their lack of cooperation can lead to resistance and withdrawal.
What The Child Needs
1. To articulate how this is making them feel: The biggest driver in refusing to cooperate is not what is being asked of them, it is the feeling of being powerless, status-less, and at the whim of an adult. To overcome this, give them room to explain why they are against what is being asked of them. Seeing someone pause, listen and care about what is bothering them will go a long way in defusing their resistance.
2. To find a solution that works for both of you: Encourage them to suggest a way to get what they want that you can both agree on. (You can also suggest a solution to speed things up and arrive at peace). This is not a negotiation or bribe, but more a display of mutual respect where they cooperate with what is being asked of them, and get acknowledgement for what is bothering them.
To be clear this is not, "Ok instead of turning off your tablet like I asked, you can watch YouTube for another 30 mins instead of an hour like you want" (negotiating) or "If you stop crying and do this errand with me I'll get you ice cream" (bribing). It is, "I hear you that you don't want to watch this movie with us because your sister picked it out and also the last 3 movies we watched. You're right that doesn't seem fair. How about you cuddle up with me and we watch the movie and I'll make sure you get to pick out the next one."
3. To admit to themselves this isn't an attack on them: Build a bridge of empathy with the child by helping them see the truth in that a lot of the things they are being asked to do aren't an effort to control them, it's because it just needs to be done to keep the day moving forward.
How To Have The Conversation With Your Child
This conversation can happen in the moment as long as you are able to set aside your frustration, and maintain your composure. If that isn't possible, you can adapt it for having later that day at a time where everyone is more relaxed but not distracted.
Speaking in a calm, lower volume voice, express that you can see that something is really bothering them. Express that you want to hear what is so upsetting, but they need to first pause and take a breath. Share with them that in order for you to be able to help them, they have to explain calmly and clearly what the problem is with what you asked them to do. [Point 1 from "What The Child Needs"] Listen closely to what they say, and repeat it back to them so they can tell you are really taking it in.
Next move on to point 2 by asking what do they think would be a way for them to agree to what you are asking but also make them feel like they aren't being ignored and the problem is getting solved. This very important part of the conversation repairs the connection between you two by giving them the respect they have wanted.
Once you have come to a fair agreement and their emotions have cooled, close gently with point 3 as a way to pre-address potential future blow ups.
End the talk with a big hug, and say again what you specifically agreed to do for them so they leave the conversation happy.