well, this sounds more like a question for the apple/itunes community (apple.stackexchange.com or apple forums etc).
also see these (but I'm not sure if these links help in your case, I'm not too familiar):
https://support.apple.com/en-us/HT205220#help (attention: this might be dangerous depending on how much different the current data on the device is. I'm not sure if you could lose some data doing this)
https://hints.binaryage.com/itunes-asks-...never-set/
also see these (but I'm not sure if these links help in your case, I'm not too familiar):
https://support.apple.com/en-us/HT205220#help (attention: this might be dangerous depending on how much different the current data on the device is. I'm not sure if you could lose some data doing this)
https://hints.binaryage.com/itunes-asks-...never-set/