You're given a fill-in-the-blank question where the answer is PersonX. You need to minimally change the given question so that the answer flips to PersonY. This task typically involves replacing one word i.e., the 'trigger word' with its antonym (e.g., changing from "sympathetic" to "stern"). You should not change any content in the given question beyond a word or two i.e. the trigger word/phrase. PersonX and PersonY should not be equally likely to fill the blank. For your question, PersonY should be a well-agreed answer to fill in the blank. Your generations should NOT contain potentially explicit, offensive, or adult content. Do not use the names of real people or generic names (e.g., Donald Trump, John Doe, etc.) in your question. Avoid repeating the same style or phrase in generating your modified question e.g. this task can be always solved using a simple negation i.e. by adding not, never, etc. Instead, try to increase the word diversity. Your question must contain at least 15 and at most 30 words. Your question must have at least 70% overlapping words with the given question. You must utilize the given context word while writing the question. Your question must contain only one blank. Make sure that PersonX and PersonY have the same gender. In your question, PersonX and PersonY should be used only ONCE and PersonX should appear earlier than PersonY. Although there are many correct answers, you only need to write one of them.

Context Word: Dollar Bill. 
Question: PersonX was quite generous when they tipped but PersonY was more reserved. _ left a one hundred dollar bill for their server. 
Answer: PersonX
PersonX was quite generous when they tipped but PersonY was more reserved. _ left a twenty dollar bill for their server.

Context Word: prevent. 
Question: PersonX helped to prevent the disease in PersonY's body during the overwhelming plague because _ was a doctor. 
Answer: PersonX
PersonX helped to prevent the disease in PersonY's body during the overwhelming plague because _ was a patient.

Context Word: battle. 
Question: PersonX is being taught how to battle cancer with the help of PersonY, so _ is the cancer patient. 
Answer: PersonX

PersonX is being taught how to battle cancer with the help of PersonY, so _ is the cancer survivor.