The use of songs in advertisements varies widely. Some ads use the original audio master, while others feature reproduced versions.
 

It’s also common to see advertisements made with reproduced versions where the lyrics are modified to suit the creative needs of the ad.

Take a look at these example:

So, is it really possible to use a song in an ad but change the lyrics?
 

Why not? Songs used in advertisements can have their lyrics changed as long as permission is obtained from the songwriter.
 

How does it work?
 

The song user must obtain a synchronization license, which is the type of license required to use a song with visual media in audiovisual works, including advertisements. In the synchronization license, the user must also include the proposed lyric modifications to gain approval from the song’s owner. The songwriter has the right to accept or reject all or part of the proposed lyric changes.
 

With this license/permission, producers or production houses can safely and confidently use songs, including altering lyrics, in every ad they produce.