Work permit for foreigner (Istanbul)

Dear all,

One of my friend who is Russian got work permit for 1 year through her company but she had to resign because of some reason in 1 month. My question is, whether she can use that work permit to work in another company or after resingning it become unvalid. İt means does she has to get it once again or not?

İf anyone gives me an idea who got experience regarding this topic it will be highly appreciated.

Thanks in advance!

Rgrds.