Chosen Solution

Im replacing iphone 5 with 6… 5 has 64gb, 6 has 16gb. Is there a way to reflash the 64gb to use in the iPhone 6.

Unless you know and have the equipment to micro solder. No. Even if you could micro solder, It probably will not work. Yeah doing more research thats a solid No. 6 is made by Sandisk and the 5 is a hynix storage