I wouldn't point to Murkowski's previous votes to repeal while Obama was still President.  It is easy to vote in support of a bill that is doomed to die and worth some political capital while presenting little to no drawbacks.  But the circumstances are completely different now.  As was noted even before Trump assumed office the Republicans now own any healthcare decision.  Now there are consequences, some expected to to be quite severe, if the ACA is repealed without any replacement.  That's probably part of the reason why Lisa made that speech back in January opposing any repeal without something that fills the gaps.