Hello! if you change the bones length ( Tools - Spine User Guide: Bone length tool ) or translate them using compensation ( Tools - Spine User Guide: Compensation ) you'll still likely need to revise your animations but it should be possible.
fns लिखाwithout affecting the ik angle.
This last statement confuses me. If you edit the bones and they point to the IK, it's unlikely they'll have the exact same angle.
Did you perhaps mean the target bone position? (that's what the image you posted rather suggests)
If you want to keep the target the same, then you can change the length of the bones to make them stay inside the leg.
If you have two skins and one skin uses the leg bones as they are, then you might consider turning the first set of constrained bones into skin bones Skins - Spine User Guide: Skin bones and make a new set of skin bones for the new skin that would follow the same target the original bones followed.