How do you calm your kids down when they have a bad nightmare in middle of the night?

I will depend how severe it is, sometime i will pat her and she will continue to sleep, if continuous, i will put her at siting position and calm her 1st, after she stop her scream or cries, i will let her lay down back again and see if she continue sleeping, calmly. So far, it's kind of works, unless very severe, than you may need to carry her and calm her down, give her some secure as you don't know what nightmares they have.