Learn English – How to politely tell someone to leave a room

You can almost always say "No thank you", which is polite enough on its own, but if you'd like to give a longer response, you could say something like:

No thank you. I appreciate the offer, but I'll be fine on my own.

Sometimes making your reply a little bit longer like this can make you seem more gracious and less brusque.

If you appear to be hurt, it would also be good to say "I'm okay" so they know not to worry.

Can I order the food to go?

is a very common usage. Normally you would make such request at the time of ordering, so using order is better than have.

In:

Can I take out the food to go?

take out and to go basically mean the same thing so this statement comes across as repetitive.

However, take out is often use as an adjective describing a kind of food:

Maybe we should eat take-out food tonight.

This form is usually hyphenated.