Fixing a slipped gown strap

A woman in a dark green satin gown at an awards dinner, with one strap slipped down her arm.

BeforeAfter

KeptBanquet hall
KeptFace, hair and necklace
KeptSatin folds and drape
ChangedNeckline now has two straps
ChangedSlipped strap back on the shoulder

Keep in mind: The original one-shoulder neckline became a matching two-strap neckline, so the neckline shape changed too.