If you have a discussion you want to log in in Lighthouse that's outside the regular 1 on 1 schedule, just scroll down to the Past 1 on 1s area for that team member's 1 on 1s and click "Add a Note":

Once you do, you can add any notes from your discussion, set and email action items, and if the discussion happened on another day, click to change the date:

Once you're done, just refresh the page and it will be added in chronological order to your timeline of past discussions:

And if you make a mistake, just click the trash can on the right to delete it and you can re-try by clicking the "Add a Note button again. 

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