The answer to 'how to repair roof vent' is to first inspect the vent for any cracks, damage, or loose components. If the vent is in good condition, you can simply tighten any loose screws or nails. However, if the vent is cracked or severely damaged, it will need to be replaced.
To replace a roof vent, you'll need to carefully remove the old vent, clean the area, and then install a new vent according to the manufacturer's instructions. Make sure to use the proper sealant and fasteners to ensure a secure, weatherproof installation. It's also a good idea to check the roof flashing around the vent to ensure there are no leaks.