How to make up with best friend?

my best friend and I had a little arguement today.. we're supposed to meet after school.. but i've a science project meeting after school and was 2 hours late.. when i called him he already took off.. he sounded upset on the phone.. what should i do??How to make up with best friend?
Just tell him you're sorry about the mixup and thank him for waiting for however long he did.





If there's something you could have done differently, tell him how you will handle it next time.





Then it's up to him to decide to accept your apology.How to make up with best friend?
Call him and be like ';Sorry I had my Science thing and my grade was depending on it.'; Then, apologize for the argument earlier. It should be all cool.