There are two reasons why you may not be able to edit a player's details. The first is that they are registered with one or more leagues on play-cricket. If that is the case then you need to withdraw the registration(s), make the change and then resubmit the registration(s). The second is that the record itself is the player's own login (no * after their name in the list). In that case only the player themselves can do this, by logging in and using the Edit Account option.
If you have any problems with a person's account and the person is not registered with Play-Cricket, please contact the Helpdesk firstname.lastname@example.org for help.