Answer:
a) 切 -> 召 -> 呈 -> 現
切 SETSU, ki(ru), ki(reru) - cut
召 SHOU, me(su) - summon, wear, take
呈 TEI - offer, present, exhibit
現 GEN, arawa(reru), arawa(su) - present, appear, show
b) 架 -> 棋 -> 期 -> 肺
架 KA, ka(keru), ka(karu) - hang, build (a bridge)
棋 KI - go, shogi, Japanese chess
期 KI, GO - time, period, term
肺 HAI - lung