Blind transfer to extension's voicemail


Does anyone knows how to blind transfer to an extensions voicemail directly?

I should have elaborated by question…

I am using SPA504G and the blind transfer using ## + * {extension} works without any issue.

Its just I dont know how to use the bXfer feature on this phone. I also have 1 expansion module SPA5000S attached to this phone.

Any help will be greatly appreciated.