AWS SDK for .NET Documentation
ModifiedSinceDate Property
AmazonAmazon.S3.ModelCopyObjectRequestModifiedSinceDate Did this page help you?   Yes   No    Tell us about it...
Copies the object if it has been modified since the specified time, otherwise returns a PreconditionFailed.
Declaration Syntax
C#
public DateTime ModifiedSinceDate { get; set; }
Remarks
Copies the object if it has been modified since the specified time; otherwise returns a 412 (failed condition). Constraints: This property can be used with ETagToNotMatch, but cannot be used with other conditional copy properties.

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)