Allow (verb): to let something happen (it is okay). A mother can allow her son to eat ice cream after the dentist.
Appointment (noun): a meeting with someone for a certain time
Receptionist (noun): a person who works at the front office. A receptionist makes phone calls, gives you forms, and helps you with appointments.
Call __ back (idiom): to return a phone call. You may have to call back the doctor’s office if the receptionist calls but you miss the call.
Get back from (idiom): return from somewhere. You can get back from a tennis appointment (to your home) in the evening.
Sign (verb): to write your name on something. You usually have to sign your name when you use a credit card to pay a restaurant bill.
Signature (noun): the name you write down on the form when you sign it. You can write it in a special way.