Is there a setting to make mobile data take over for poor wifi?

[nonie]

At one time there was a place to check if wifi was bad, data would click on. Can't find it. Using att. Anyone know where I could find it? Or if it's gone after last update?
TIA

 

[can3gxw]

Settings > Wifi > Smart Network Switch

 

[nonie]

Thanks, had just found it. Couldn't remember where it was.