If you wish to change from single honours after year one to joint honours do you have to reapply or is it the same as the reverse where you just talk to department heads and cover the modules from year one in year two?
It is possible to do, but as you will have missed some modules from Year 1, they may have to get special permission to shuffle the modules about to ensure you cover all the required topics. If it can't be done, you might have to repeat part of year 1 to catch up. You must contact your current and the other department as soon as possible, and get it sorted before the summer. It should be fine, but get it sorted asap after your exams. Good luck!