Calender problem. I have a 5S using 7.0.6. When I transferred the info from my old iPhone 4 there was a problem with the calender duplicating entries so I stopped using the calender on my iPhone and turned access to the cloud off. I continu

Calender problem. I have a 5S using 7.0.6. When I transferred the info from my old iPhone 4 there was a problem with the calender duplicating entries so I stopped using the calender on my iPhone and turned access to the cloud off. I continue to use the calender on my MacBook and iPad and this works quite well syncing through the cloud. Now I want to have it working properly on all three devices. If I reinstall the OS on the iPhone will the cloud automatically sync the calender to my iPhone or will the iPhone push the blank data to the cloud and erase everything?