Short answer. The Labor Code measures the probationary period from the date you started working, not from a role change, and caps it at six months. It does not describe a new assignment as a basis for resetting that clock, and once you have been allowed to work beyond the original probationary period, the law already treats you as a regular employee.
What the law says
Probationary employment shall not exceed six (6) months from the date the employee started working
Labor Code, Article 281 — Probationary Employment. Read the full provision →
What the six-month clock is tied to
Article 281 anchors the probationary period to a specific event: the date the employee started working. It does not tie the period to a job title, department, or assignment. The article speaks in terms of when the employment itself began, and it fixes six months from that date as the outer limit, subject only to the apprenticeship exception. On its face, the article gives an employer no textual hook for measuring a fresh six months from a later date simply because your duties changed.
The consequence once the original period has passed
The article also provides that an employee who is allowed to work after a probationary period shall be considered a regular employee. If you were already allowed to continue working past your original probationary period, that provision already applies to you. A later move to a new role does not appear anywhere in Article 281 as an event that undoes regular status or reopens the probationary clock — the article simply does not describe reassignment as a trigger of any kind.
What this article does not settle
Article 281 is written around the initial hiring and the first six months of employment. It says nothing about internal transfers, promotions, or changes in role, and it does not spell out what happens when an employer tries to treat a reassignment as a fresh start. Where your case turns on whether a particular new-role arrangement can lawfully be called a new probationary period, that is a question this article's text does not directly answer, and it should not be treated as settled either way from this provision alone.
What is worth keeping track of
Because the article measures the period from your original start date and treats being allowed to keep working past it as making you regular, the useful record to hold on to is your actual hire date, any document marking when your first probationary period ended, and whatever was communicated to you about the new role. Those dates are what a reading of Article 281 would actually turn on, rather than how the employer chooses to label the new assignment.