The phrase "a different proposal" is correct and usable in written English.
You can use it when referring to an alternative suggestion or plan that differs from what has been previously mentioned.
Example: "After reviewing the initial plan, I would like to present a different proposal that addresses some of the concerns raised."
Alternatives: "an alternative suggestion" or "another option".
After much debate, a different proposal was abruptly proposed and adopted, essentially reviving previous Massachusetts tax laws.
A different proposal was then accepted by the publisher a couple of months later.
"I have a different proposal for you," Mr. Trott said, according to his testimony.
I have a different proposal, perhaps more in keeping with the peculiar nature of the peril.
Last year it came back with a different proposal: to lease the stadium for 99 years.
Yahoo countered with a different proposal in June that Alibaba found unjustifiable, he said.
The one that [Leeds chief executive] Gary Hetherington explained to me about a fortnight ago was a completely different proposal.
But the real test remains what will happen after the Senate, as the proposal will go to a House-Senate conference committee where it must be meshed with a far different proposal sponsored by Representative Michael Oxley, an Ohio Republican and chairman of the House Financial Services Committee.
Assuming it is passed by the Senate, the legislation will go to a conference committee to be reconciled with a substantially different proposal, already passed by the House, that is favored by the accounting industry.
If so, the proper response to the objection is to not to retain the basic shape of (1) and add to it in various ways, but to offer a quite different proposal, i.e. one that is a non-modal in character.
Kopp said the project is a far different proposal today from what was called for in a successful 2008 ballot measure that provided more than $9 billion in bond funding for the project.
