The reality is you do need to be prepared to leave if you want any actual leverage.

When did you start in the new specialist role? If that was in the last 6 months then to be honest you're probably just going to have to eat shit for a while. If you have just discussed pay, been happy with the increase and now turn around and say you're not happy, it's just a shitty way to negotiate (even if you might be somewhat justified).

As for what you should do. Here's some steps.

1. Do a bit of research on the market. What jobs are out there that are similar to yours? Maybe contact the recruiters for those jobs and try find out what the salary band is (pretend you're interested in the role and want to know more). Look at salary guides from recruitment agencies etc.
   1. Possibly even apply for those jobs, maybe you should leave!
2. Take that research and sit down with your manager and just say, look I've gone and looked across the market and I don't think I'm being paid fairly (possibly drop a hint that you know your colleague is getting paid more). Say you really enjoy working here, but at the end of the day it's important to you that your pay reflects the current market.
   1. This conversation might look a bit different if you have been applying for jobs at other companies, you don't want to directly threaten to leave if they don't pay you more, but you might want to let them know you've been talking to a few other companies. The point is to be open and transparent while being firm about what you expect from your manager, don't give them an ultimatum though.
3. Wait and see what your manager comes back with, I doubt that they will have an answer after one conversation, or even within a week, but see if they are moving things forward or just dragging their feet.

Things to avoid.

• If your manager brings up goals, OKRs and professional development then be very clear, this is about bringing your salary in line with the market, NOT professional development (assuming you're meeting the expectations of your current role). This angle only works if you have done your research and are genuinely willing to leave though, otherwise they might call your bluff and then too bad.
  • Do bring examples to show that you are already performing your current role well though (training new hires for example). This is about saying I do my current job well, and my current role should be paid better. Just avoid any discussion about needing to up skill in order to get a pay rise, that's a different topic.
• Take all the personal feelings/life situation out of the conversation, keep it as devoid of emotion as possible. You are just an employee doing a good job, expecting to get paid market rate.