Reception is not understaffed. It's outnumbered.
Between 8:30 and 9:15 your front desk is checking in the morning list, taking payments, and answering the phone. It cannot do all three. The calls that ring out during that window are not from people with a mild query — they're often the ones in pain who will ring the next clinic within the minute.
The same thing happens at lunch, and again in the last half hour of the day. It is not a staffing failure; it is arithmetic. One person cannot be in three conversations, and hiring a second receptionist for three busy windows a day rarely stacks up.
What you can change is what happens to the call that didn't get answered. Right now, nothing does.