Speaker Johnson orders flags be flown at full-staff during Trump inauguration

Mike Johnson announced that flags will fly at full staff during Donald Trump's inauguration, overriding President Biden's order to keep them at half staff for 30 days in honor of Jimmy Carter. Johnson plans to lower the flags back to half staff the day after the inauguration.

What event prompted President Biden to lower flags to half staff?

When will the flags be lowered back to half staff according to Johnson?