You might have Tier 4 immigration permission (leave) that allows you to work, but you leave your course or take a break from it before you have completed it. This includes the situation where your Tier 4 sponsor withdraws sponsorship temporarily because you need to re-sit exams or repeat some of your course and do not need to be in the UK before you re-sit or repeat, or your sponsor might lose its licence.
In these situations, the Home Office will usually curtail your leave so it ends earlier. The Home Office publication, Employer's guide to right to work checks states that you may continue working until the new end date of your Tier 4 leave. If you submit another application before that leave expires, you should be able to continue working beyond this date.
For full details of when employers may and may not employ you in these and similar circumstances, see information under the heading, 'Impact of a change of circumstances on a Tier 4 points based system student's right to work' in the Home Office publication, Employer's guide to right to work checks.