The Cheers & Frasier Wiki
The Proposal
Season 5, Episode 1
Air date 25 September 1986
Written by Peter Casey and David Lee
Directed by James Burrows
Episode guide
Strange Bedfellows - Part 3
The Cape Cad

We finally found out who Sam's telephone proposal at the end of the last episode was to - Diane! But Diane fears that Sam is merely on the rebound after breaking up with Janet, so asks him to repeat the proposal in a more romantic occasion, but when he does (on a boat), she refuses, causing Sam to make her walk the plank. Later Diane says she does want to get married, but Sam has now retracted the proposal.