Huge
It depends on the car you have. On some cars on the rear you can have both brake shoes and brake pads and with this set-up yes you can remove the pads without affecting the hand brake. However, on other cars you have either old type shoes or pads and with these you have to release the hand brake. If you raise the car on axles stands or similar the problem of not having the brake on is solved.

bandit_60
nope ! the parking brake has to be completely off.

smgray99
Just disengaging the brake should be enough. Keep in mind that the new pads will be thicker than the old (obviously) so you will have to press the wheel cylinders in plus may have to adjust the cable to allow for the difference anyway.

roger
most cars have some type of self adjusting brake cable to keep the E brake tight as pads wear down. You have to loosen the cable all the way one way or the other when putting in new pads. Personally, I always buy whats called a loaded set of calipers. This is calipers with new pads installed. Any time a brake shop needs to do pads, its best to use new calipers and pads for optimum braking performance. Its cheaper to buy loaded calipers, and easier to install. If you are not sure about the E brake, you should already have a shop repair manual that will show you what you need to know. Using or reusing a caliper with a piston that has been extended past the brake seal into the air. can lead to problems later on in the future with possible dirt and rust/and or water damage from being exposed to the outside air. Far better to have a clean undamaged unrusted caliper , than one that has already been into the outside air for awhile. And often times the bleeder screw will rust shut too, or worse moisture gets inside and can damage internal parts as well. Its good that you are asking questions and makeing sure to get it right. Take your time, and get a shop manual if necessary , it wil help you in the long run too.