<prompt> Human: I used to be account consultant on a very manual client for about 2 years. 10 months ago I was promoted to a larger client on a different platform. I trained my replacement on the ins and outs of that manual client and things have been going smooth. He trained his back-up so that there was always someone who could do the job.2 weeks ago his back-up got fired, and the stress mustve gotten to him because this morning we find out that he will no longer be returning to work.We have not heard anything from our managers yet but I know that I am the only subject matter expert on this client left so I will undoubtedly be asked to temporarily take over the client andor train a replacement.I havent been called into this meeting yet but I feel like I should set up some ground rules while fearing that my managers could still fire me at any point if I simply say no to going back to this old client.Based on my history with this company, they appreciate me a lot so I do also feel a little more job security than others in my department, but they are incredibly hesitant with handing out pay raises or bonuses. the last time I went above and beyond, it took the company 6 months to give me a pay raise, and because that occurred in the 2nd half of the year, this disqualified me for a yearly payraise their company rules. I feel that if I took on this old client, I should ask for an immediate pay raise because I am doing the work for 2 people... but Im not sure how to word this so that I dont sound like a dick who just wants more money.Also I will be out of town this Thursday and Friday so the timing is super inconvenient!Any piece of advise would be greatly appreciated!  <response>: fearing that my managers could still fire me at any point if I simply say no to going back to this old client.Why would they fire you? Theyve already lost 2 people and youre the only expert on staff. Youve never been more valuable to the company than you are right now. If you have ambition to advance then take on the responsibility but use your leverage to get more pay and a better title. If you dont and are happy where you are, tell them no. Whatever you do though, dont take on more responsibility without compensation from this position of power. 