Creative > Ads > Master Ads > [Existing_Ad] > Edit
Depending on the ad format type, you can modify an ad format for an existing unattached master ad. When converting to the target ad, the default image, custom interactions, and privacy settings are preserved.
Note: The initial ad format can only be changed to a limited list of formats. If the format you want is not available in the Select New Format list, you will have to create a new ad, which may require adjustments to your ad based on the related guidelines. For more information, see Amazon Ad Server ad formats.