I have recently joined a company and now I am getting interview calls from other better organizations. What should I tell them when asked why I want to change in 4 months. My actual reason is better pay but I dont think so I can say that directly.

You can say that I'm finding it hard to fit into the team and there's lack of support. Or that the actual job is different from the original job discription that they posted

I changed my organization within one month of the joining for an opportunity way better than I could have ever dreamt of...157% hike. To this new organisation that has shortlisted you, you can either cite health/family/personal reason as an excuse to switch job within such a short span without giving the actual details or maybe even say that you have been trying to apply (this new organisation that has shortlisted you) for long and now that you have the opportunity you wouldn't want to miss it. Just glorify them lol

Tell them that ur supervisor is asking to relocate to a different place and that decision is making you go ahead with this change in 4 months

You say it or not that's what company is going to think 😂

I'm not actively looking for a change, you approached me and I love your company and the role more and I believed I can bring value to your company. ....that's what I told an HR and landed a job...

Frankly tell them that you didn't got what promised like they hored you as developer and assigned you as manual tester and asked to be in that role only. Anyone will understand your situation. Another thing you can say is that your new boss is very toxic. They are not going to verify.

Man, don't switch without a concrete grievance at the current org. Is the culture good, are the peers and management treating you well,how's the learning curve like? If your answers are positive for all of these, then stay put. Making hikes/money the sole reason to switch doesn't reflect well on the integrity you have.