[Sonnyday]

Originally Posted by arunp

I would have used the following sentences, I am open to corection though

1. Someone in his/her retirement is called a senior citizen.
2. People in their retirement are called senior citizens.

Me too! Especially, it's about taking a test/an exam in school/college or at university. Same applies to formal writing such as application letters, government correspondence and compositions/essays, etc.

In day-to-day conversations, one can use the "they" form for the third person whose gender is unknown to the speaker.