Changing password asp.net identity -

is there quick way verify user exists , based on existence of user name user id?

(i.e. user has user name , adds change password)?

i think this... string userid = user.identity.getuserid(username);

i looking quick way local users change password if need be.

user.identity.getuserid() return id of current logged in user. usermanager can user username this

var user = usermanager.findbyname("the username here"); 

then can change password usermanager again

usermanager.changepassword(user.id, "oldpassword", "newpassword");