在Apple中更新免费配置文件

Last week I used the free provisioning profile method to install my app on my iphone. it's really important that it works on thursday morning, but since the free provisioning thing is only valid for a week, it will run out the night before thursday. and i don't have access to my other computer within wednesday night and thursday morning, so I need to renew my provisioning profile in advance. is that possible? i never renewed it so I have no idea how that's supposed to work. also if i would renew it, do i have to install the app again? Last week I used the free provisioning profile