I want to ask one thing. Sometimes we hear people say
my email ID has changed.
As per my understanding present perfect tenses need a subject which is missing above.
I find these sentences little bit weird because I think we should have subject in using present perfect if it is not passive one.
I think we should say
- my email ID is changed
or- my email ID has been changed.
Please help me out to use present perfect effectively, the present perfect tense make me confuse.