You've got to accentuate the positiveYou’ve been pushing a proposal, but now you’ve reconsidered.
Eliminate the negative
-- Johnny Mercer & Harold Arlen (1944)
Your priorities have changed. What you thought were benefits turned out to have unacceptable, previously hidden or underestimated costs.
What you thought were unacceptable costs, now seem to be not too bad, after all.
Time to reverse yourself, but not look scatterbrained or hypocritical in the process.
How to do this? Just consider: what someone may call “tact,” another will call “lying.” Same thing, just two ways of looking at it. It's a matter of value priorities. Characterizing an action "tact," prioritizes concern for other peoples' feelings over truth-telling. Calling it "lying," gives higher priority to truth-telling than to concern for peoples' feelings.
Consider another example: what some people may say is “plain truth” or “forthrightness,” others will call “insensitivity” or even “cruelty.” Again, it's a matter of value priorities: openness vs. not upsetting people.
To promote a change of course, you will have to reorder value priorities. You’ll need to know how to commend the values you now avoid even if previously you disparaged them. You’ll need to know how to disparage the things you now want to avoid even if previously you commended them. If you can handle these inversions skillfully, switching sides should be no problem.
But think it through first. Reversing yourself too frequently undercuts your credibility.
For references and to learn how this reversal process works, see see Mechanisms for Policy Reversal