Upon release, "A Change of Heart" received positive reviews from contemporary music critics, who praised the lyrics and production.

[6] Containing a retro sound, the track's light and airy production consists of synthetically charged choirs,[2] a percolating rhythm,[7] simple three-note repetitions,[8] a pop hook, 808 beats, a backing drum beat, jittering guitars, a portamento keyboard riff, quietly reverberating and meandering synthesiser pulses,[9][10] a whirring synthesiser solo,[11] lightly-tapped synth pads and a calming rock instrumentation.

[12] Ryan Reed of Rolling Stone described it as a "John Hughes-worthy synth-pop ballad", while James Grebey of Spin called it a "relaxing, floaty throwback to decades past" and Chris Ingalls of PopMatters said it "[sounds] like it was transported from 1987 and wouldn't sound at all out of place on some big-haired college radio DJ's late-night playlist".

[12] Returning to the theme of technology explored in "Love Me",[9] the song analyses connection in the digital age, describing a partner more interested in being on their phone than with the relationship.

Billboard deemed "A Change of Heart" the best rock and alternative song of 2016; describing it as an "incandescent synthpop tale of a relationship crumbling apart", editor Chris Payne praised the songwriting, narrative and alluring quality.

[17] Spin ranked the song at number 59 on their 2016 year-end list, with Anna Gaca commending the "exquisitely" gentle sound, haunting synth and "tragically" ironic depiction of modern love, calling it a "wooning, shimmering heartbreaker of a pop ballad".

[18] NPR included the track on their mid-year best of 2016 list; Daoud Tyler-Ameen declared it the most undeniable song from I Like It When You Sleep, for You Are So Beautiful yet So Unaware of It.

[11] Neil O'Sullivan of Financial Times called "A Change of Heart" excellent,[13] while Maledine Roth of MTV News said the song is a "soul-wrenching (but admittedly beautiful) heap of sadness".

[21] Celia Cummiskey of Euphoria Magazine highlighted Healy's delicate vocals and ability to mask a complicated emotional dilemma within the song's "deceptively upbeat" sound, while comparing "A Change of Heart" to Peter Gabriel's work in the 1980s.

Club said Healy "upends the sensitive-poet stereotype with a knowing wink" and Rhian Daly of NME called the song the most self-referential track on the album.

[26] The black and white visual is based on Federico Fellini's film I clowns (1970),[27] while also taking inspiration from Michael Jackson's tribute to Charlie Chaplin, The Wiz (1978), Gene Kelly and Bob Fosse.

[29] Reed also deemed the visual a tragicomedy, praising its vividness while noting it "[charts] the highs and lows of a tragicomic clown romance".