Unattach rhymes with:
attach, reattach, attach, detach, reattach, stach, tatsch, attach, bache, batch, brach, bratsch, catch, detach, dispatch, drach, flach, gach, gatch, hach, hatch, kach, krach, lach, lache, latch, latsch, mache, match, matsch, mismatch, overmatch, patch, rach, reattach, rematch, scratch, snatch, stach, tatsch, thach, thatch, tkach, vlach
Unattach sounds like:
umetsu, undock, unhitch, unit's, unitas, united's, unitek, unites, units, units'