Originally Posted by
DuneMentat
Your C1/D visa is only valid for Emirates Airlines so you will need to reapply with your new employer. If you have a B1/B2 (tourist) visa it will not be cancelled
Not strictly true DuneMentat. If the annotation field on your crew visa is blank then you can use it for another carrier. However if it is annotated with Emirates Airlines then yes you need a new visa.
Some of the EK crew visas have this and some don't. I had many confused looks at the US Embassy in Australia as they said they'd never seen the annotations before and I said it must be a Dubai/EK thing.