how do you replace handle on sterling silver teapot?
Answers:
If you have the handle, take it to a silversmith and they can solder it back on in most cases.
If you have lost the handle and want to restore the teapot to its original look you might need an antiques restoration service... assuming the teapot is old. If it is a new one and/or the design does not have to be authentic to the original, again, a silversmith could probably fabricate you a serviceable handle and attach it.
Other answers:
Have it silver soldered back on.
Have it silver soldered back on.