A phrase that basically means 'change your mind a second time to go back to your original idea'
I am interested in knowing what words/phrase/idioms I can use to express a double reversal of decision.
To illustrate that with an hypothetical example to clear any confusion that may have risen :
I had the idea of buying a phone for someone, decided against it, and then thought about it a bit more and ultimately chose to do it.
What do you think about saying "I changed my mind, and then I changed my mind back." in that context?
To come full circle could work. Here are several definitions and examples of the phrase:
To return to the same situation or attitude you originally had. I left publishing, tried teaching, and now I've come full circle back to publishing.[1]
When something “comes full circle,” it completes a cycle, returns to its beginnings: The novelist's vision of human life has come full circle—from optimism to pessimism and back to optimism again. [2]
In the comments below, an idiom describing "returning to a starting point after going around in a full circle[,] especially in the context of unsuccessfully trying to find one's way in a maze" was requested.
I would suggest Going around in circles or Walking in circles. Examples:
To move over and over on a circular path. The model plane went around in circles until it ran out of fuel. The oxen went around in circles, pulling along a beam that was connected to the millstone.[3]
To act in a confused and disoriented manner. I've been going around in circles all day. The children have been going around in circles, waiting for you to arrive.[3]
To keep going over the same ideas or repeating the same actions, often resulting in confusion, without reaching a satisfactory decision or conclusion. We're just going round in circles discussing the problem. We need to consult someone else to get a new point of view. Fred's trying to find out what's happened but he's going round in circles. No one will tell him anything useful.[3]
This expression is frequently used in the context of being lost. Upon realizing that one has returned to a location one has already visited, one might remark, "it looks like I've been walking in circles".
Citations:
1The Cambridge Dictionary of American Idioms © 2002
2The American Heritage New Dictionary of Cultural Literacy, Third Edition © 2005
2McGraw-Hill Dictionary of American Idioms and Phrasal Verbs © 2005
I might suggest that you have flip-flopped on the idea of buying a new phone but ultimately decided to purchase it.
I might also say that you waffled on the idea before buying your new phone.
Consider reconsider.
to consider again, especially with a view to change of decision or action: ex., to reconsider a refusal.
Parliamentary Procedure. to take up for consideration a second time, as a motion or a vote, as with the view of reversing or modifying action taken.
While it does not always mean you will reverse the decision, it means you will think about it again.
I had the idea of buying a phone for someone, decided against it, but on reconsideration chose to do it.
Did a 360.
Two 180s, a Uturn followed by a Uturn.