JDA - How to convert the "Member" Object to a "User" Object and not vice versa?

I am trying to code a command to DM a mention person !dm @JohnDoe, However, the mentioned user is a "Member", and DMing requires a "User".

Member mentioned = event.getMessage().getMentionedMembers().get(0);
mentioned.openPrivateChannel().queue(DM -> { //Program Expected User not Member while "mentioned" is a Member. 
DM.sendMessage("You've been DMed.").queue(); };

Note : This isn't a duplicate of JDA - Converting "User" to "Member", I am converting from Member to User, not User to member.

I am trying to know how to convert from Member to User and not vice versa. Also, If there's another way than converting please let me know. Thanks, Bedo