Simply terminate your work and let the other individual in or, at least, ask if she has a small job or would like to interrupt your work. Be respectful of others who work in your school by considering their needs and schedules, especially when you may be in the position of interfering with others accomplishing their work. Schedules in schools apply not only to time but also to space. If another individual is scheduled to be in your room or spot in the hallway at a particular time, you need to vacate willingly and cheerfully on time . Schools in which all of you will work are overcrowded.
Space is very precious.
Chances are you will have to shift to different locations during your time in your school. Be considerate of others in your use of space and always be flexible. Most schools have rules and handbooks. If your school has a handbook, your principal will give you one on an early visit of yours to the school. Read the handbook and obey all of the rules in it.