When a foreign employee plans to resign from a company, he/she might meet these circumstances:
Having bad relationship with the company;The HR of the company doesn't know or forget to cancel the foreigner's work permit;
The foreigner leaves the company directly without submitting the resignation.
Transferring to a new company would become very difficult if you meet any circumstance above, because you have to provide these two documents when applying for a new job:
1, The release letter;
2, The Cancellation Letter of Work Permit
Both of these two documents should be issued with the help of your previous company. Therefore, you MUST take these two documents before leaving the company.