Change to a new sponsor with an NOC - What about the visa of my spouse & kid

Hi, Greetings to everyone in qatar living, I have a doubt regarding sponsorship changes thro NOC, At present i am working in an company and i expect my company to give notice to me after two or three months as there are no more projects in the company, Currently my wife and daughter are living with me in my sponsorship.
If given NOC and if i get a job in qatar whether it is required for me to cancel their visa first and then cancel my visa and then exit the country and come in a new visa and complete all my formalities and then apply visa for them.
Someone please help me with this, as my daughter is studying her it will create lot of problems for her.
Thanks you all in advance for sharing me some useful information......
I think companies do not prefer to give a release as now it is very difficult to get new visa, Has any body been in the same circumstances,
Please share with me some information.
Insted of Getting NOC, transfter your visa to the new company/sponsor. then no need of going out of the country and come back.