Can I obtain a reentry permit in the morning and leave the airport before my flight at night?

The user seeks clarification on whether they can obtain a reentry permit at the Suvarnabhumi immigration office in the morning, leave the airport, and return later for their flight. A comment suggests that the reentry permit can be obtained on the day of departure after checking in with the airline, but returning to the restricted area of the airport is typically not allowed after exiting.