Final answer:
Once a Form 4 has been filled out, it becomes invalid after a certain period of time, usually specified by the organization requesting the form.
Step-by-step explanation:
Once a form 4 has been filled out, it becomes invalid after a certain period of time. In general, the validity period of a filled form 4 can vary depending on the institution or organization that requires the form. Some organizations may specify a specific expiration date or time frame in which the form 4 must be submitted. If the person is not admitted within this validity period, the form may need to be re-filled and submitted again.