I had to replace my bathroom sink and the sink drain and trap do not line up. The trap is pvc as is the pipe coming off the original plumbing. There is pvc fittings attached to the original metal plumbing. How can I remove it safely so I can fit new piping and adust for the drain in the sink which is further back than the old sink drain was?

How can I remove it safely so I can fit new piping

That probably is not really necessary.

Show us some pictures of the piping under the sink.