There are many retired people living in the world
retired and often
retired
Scottie Pippens number at Central Arkansas to be retired. (true by the way)
After he retired, he got his pension.
Withdrawn or repeal?
The participle in the sentence is "retired", which is used to describe the couple.
Our neighbour , the retired engraver, is always frustrated.
You capitalize Judge Smith. You do not need to capitalize retired as it is not part of his title.
the footy fans got together for the millennium of their favourite retired player
The retired teacher was beloved by all who knew her.
He was an able seaman for 30 years, then he retired from the merchant navy.
In the sentence "The retired couple set off for Phoenix in their motor home," there isn't a participial phrase present. A participial phrase typically includes a participle and any modifiers or objects, and it often describes a noun. In this case, "retired" is a participle describing "couple," but it isn't part of a participial phrase.