To request a waiver under Harvard's Open Access Policy, simply use the Waiver Generator and supply the information requested there. A formal letter notifying you of the waiver of the license will be emailed to you at the address you provide.
Even if you are required by a publisher to waive the license as a condition of publication, chances are you can still make your article publicly available in the Harvard repository, as explained further below. Thus, whether your article is under a waiver or not, you should still deposit the final manuscript in DASH.
The repository accepts not only articles covered by the license granted to Harvard under the Open Access Policy, but also articles not covered by the license.
Even if you take a waiver, the publisher's agreement may provide, or you may be able to negotiate, sufficient rights to allow copies of your article to be made publicly available in the Harvard repository. The publisher may ask that certain conditions be met, some of which the repository can accommodate (for example, an embargo period during which the article will not be made publicly available).
Information about publishers' standard policies on open access is available from the SHERPA/RoMEO project (though Harvard has not verified the accuracy of that information).
Further, even if your article cannot be made publicly available, you are encouraged to deposit a copy in the repository under the "metadata only" option, which stores a copy in the repository for archival purposes and provides bibliographic information that can be included in an online index of scholarly articles by Harvard members.
The bibliographic information will be made available for broad harvesting and indexing by search engines, in order to increase awareness of your article. This will enable your article more readily to be found, even if a copy cannot be made available to others through the repository.