Employment Advice

Hi everyone, I could use some advice. I’ve been in my current role for six years and recently realized that I’m being paid significantly less than some of my colleagues who are in similar positions. I know this because two of them are my friends and shared their salaries with me.

I want to approach my manager to discuss a pay raise, but I’m not sure how to do it without mentioning that I know what others are earning. Any tips on how to handle this conversation professionally and effectively?