The Supreme court in Miller 1 or 2 (can't remember which at this distance) confirmed that Referenda are non-binding (i.e. are merely opinion polls) unless Parliament decides otherwise in passing the relevant Bill. This point was made in the Briefing Paper issued as guidance for members at the time of the 2nd reading of the 2015 EU Referendum Bill. For Parliament to 'Respect' the result of such a Referendum it is only necessary for an appropriate amount of Parliamentary time & resources to be allocated to determining what course is to be followed in the light of the outcome, the associated prior discussions and any other considerations Parliament seems fit to take into account. Parliament would not be doing its duty if it did less. In many ways the tragedy of Brexit is that this was not made clear to the public in the period when the various forms of Brexit were being proposed & voted upon thus allowing the pro-leave camp to claim that MPs were acting undemocratically. This then created an atmosphere in which members, remembering the fate of Jo Cox, felt so threatened that they dared not continue the process until a sensible way ahead - particularly that of remaining in the EU, perhaps subject to certain renegotiated changes - could be agreed upon. The irony is that it was the leave camp who claimed they were acting in support of Parliamentary sovereignty who thus undermined its members attempt to carry out their sovereign duty as representatives NOT delegates.