Question about access to phone room during Internet installation

Hi, I have question about access to phone room during Internet installation.

I recently moved in to an apartment and the previous resident was also using Telus for their internet, so there's ethernet cable coming out from the wall which they used to connect the Telus modem.

In this case, does the technician still have to access phone room during the installation?

Or can I just plug in the ethernet cable to my new Telus modem and no need for the technician to access phone room?

Would appreciate your comment if anyone knows about this, thanks.