コウ, さら, さら.に, ふ.ける, ふ.かす
grow late, night watch, sit up late, of course, renew, renovate, again, more and more, further
JLPT3 G7 S7 F861
As per 丙# (spread) + 攴 action indicator → stretch a rope (compare the derivative character 綆, a rope attached to a well bucket). The meanings *replace* and *change* likely owe to the drawing of fresh well water to replace that which has been used, or dried up. (Still) *more* and *further(more)* are borrowed meanings, as are *grow late* and *stay up late*.
[Full Kanji Etymology List]