As there are no technical "phone logs", which are automatically created by your phone, you basically edit notes.
In general notes may be processed up to 60 minutes after the creation of each user. Only if you have extended user rights, you can edit the entries permanently.
If you hover over a not on the status page, you see the pen icon to edit the note.
If you open up the note you find the link edit in the right column. If you do not see this link, you do not have sufficient rights to edit the note.
As a user with extended rights, you can also delete the note. First click edit note and then go to the delete link in the right column.