Change jobs possible but with approval only

Hi all,

I am in the process to take another job. I have an offer and I am ready to go.

In order to check if I am able to take the offer I was asked by the new employer to confirm with Arbeitsbewilligungen Zürich if there are any restrictions.

I got the following answer today from Arbeitsbewilligungen:
"Stellenwechsel möglich, jedoch nur mit Bewilligung (der Antrag dafür ist uns vom Arbeitgeber einzureichen)"

I wanted to know what it really means:
- The new employer needs to request it officially ?
- Could it be rejected ? Or is it only formalities
- How long such approval would take ?

The idea would be to resign from the old position still this year. But, due this result, I have no idea of what could I do.

Anyone that was already in this position ?

Thank you all.

esp