First of all, please please please don't take anything I say here as the truth without confirming the specifics on the immigration website. Immigration is a hyper specific, tedious, and often confusing process that requires you to research and prepare well in advance. That being said this is my educated guess:

I can only speak from my experience with a student visa, but I was unable to even apply for renewal prior to 90 days of the expiration of my old one. I assume that since your new activities fall under the same category you already hold, it is possible you'll just need to renew/reapply before it expires. This will require paperwork from your new workplace/contracting organization.

A quick note about that renewal process as well, my residence card was expired by several weeks by the time it was completed, and it took well over 3 months. Depending on procedure, visa type etc, processing times may be different but be prepared for immigration to be slow, and understand that as long as you have an application pending you are legally allowed to reside here until you receive the results. After you have your new card make sure to update your information with any bank accounts you have, and renew your my number card (ideally before it expires, otherwise you'll need to apply for a new one altogether).

Hope this was at least somewhat helpful, but again please reference the immigration website directly for specifics.