She's an architect, isn't she? She's an architect, isn't she?
Affirmative sentence + negative tag: You're Tony, aren't you?
Negative sentence + affirmative tag: He isn't a pharmacist, is he?
I'm ......, aren't I?
You're ......, aren't you?
He's ......, isn't he?
She's ......, isn't she?
It's ......, isn't it?
We're ......, aren't we?
They're ......, aren't they?
I'm not ......, am I?
You're not/You aren't ......, are you?
He's not/He isn't ......, is he?
It's not/It isn't ......, is it?
We're not/We aren't ......, are we?
They're not/They aren't ......, are they?
1. I'm late, aren't I? 
I'm late, amn't I? 
2. No one, everyone and someone use singular verbs but plural question tags and 'they'.
No one is in the office, are they?
Everyone is here, aren't they?
Someone is on holiday, aren't they?
3. We respond to a question tag with:
a short affirmative answer - Yes, they are.
or
a short negative answer or "No" + extra information - No, he isn't. He's Italian.
No, he's Italian.
They're not in London, are they? No, they're in Paris. 
Hans is 35, isn't he? Yes, he is.
We're not late, are we? No, the meeting is at 2 o'clock.
We use a short answer when we can answer a question "yes" or "no". It's more polite than just saying "yes" or "no" alone.
Usually, it isn't necessary to repeat the information in the question.
Is Jane your sister? Yes, Jane is my sister. [not recommended]
Is Jane your sister? Yes, she is.
Question: | 'to be' + subject + adjective/noun | Is she American? |
Affirmative answer: | Yes + subject + 'to be' | Yes, she is. |
Negative answer: | No + subject + 'to be' + not | No, she isn't. No, she's not. |
Note that we don't use the contracted form for affirmative answers.
Are the flowers red? Yes, they are.
Is she in a meeting? No, she isn't. She's in a taxi.
Are Jill and Ben on a business trip? No, they aren't. They're on holiday.
Are you French? No, I'm not. I'm Swiss.
Are you Irish? Yes, I am.