Originally Posted by
FBplatinum
No...
On Delta website:
Diamond Medallion Members will be eligible to use Global Upgrade Certificates to upgrade to Delta Premium Select, a new class of service on Delta's long-haul international flights that will begin in 2017. On Delta Premium Select-equipped aircraft, Global Upgrade Certificates can still be used to upgrade to Delta One™.
This mean, you are in economy , you upgrade to premium select, and from premium select to business....
No, it means that a GUC can be used to upgrade to W or J from Y. It does not mean that one must be ticketed in W to be eligible to upgrade to J.
Why anyone would use a GUC to upgrade to W, I do not know.