Android
Delete a Single Entry from Call History auf Android
The Android call log stores every call as a separate entry, grouped by contact or number. Clearing the entire list through the overflow menu removes all of it at once, which is not what you want if you only need to get rid of calls from a single person or unknown number.
To remove just one entry, open the Phone app and go to the call history tab. Press and hold the entry you want to remove until an action menu appears. Tap Delete, then confirm by tapping Delete again in the dialog that follows.
This deletes every call logged for that contact or number, not just the most recent one. If you want to keep some calls but not others, you would need to delete them one at a time, since Android does not offer a way to remove individual timestamps within one grouped entry.
Deleting a call history entry only affects the log itself. It does not remove the contact from your address book, delete any text message conversation, or block future calls from that number. If your goal is to stop being contacted, blocking the number is the better fix instead of just clearing the history.