Definitions:

1. a major change in attitude or principle or point of view noun
   • an aboutface on foreign policy
2. to change one's mind and assume the opposite viewpoint verb
   • The politician aboutfaced for the third time on the issue.
3. to turn, usually 180 degrees verb
   • The soliders aboutfaced on command.

Synonyms:

• about turn
• policy change
• reversal
• volte-face