I have been asked to look at some old admission response forms that our school mails back to applying students. This letter consists of their test scores and the programs that is offered to them. Now, since we don't have an automated system that prints out a letter based on gender, the letter uses "his/her" > 50 times throughout the entire mail.
Since English isn't my first language - I don't know if it's grammatically accurate to replace them all with "their"?