Soft-deletes the specified banner, marking it as deleted without physically removing the database record. The banner must exist and not already be deleted. Requires DELETE permission on the banner's advertiser. Returns 404 if the banner is not found or already deleted. For 90 days POST /rest-api/deleted-entities/BANNER/{id}/restore.do brings it back, links included.
using var client = new HttpClient();
var request = new HttpRequestMessage(new HttpMethod("DELETE"), "https://YOUR-NETWORK-DOMAIN/rest-api/banner/3001/delete.do");
request.Headers.Add("X-Api-Key", "YOUR_API_KEY");
var response = await client.SendAsync(request);
Console.WriteLine(await response.Content.ReadAsStringAsync());