By negotiating do you mean taking points? I can’t imagine many lenders are willing to go below prime for a 30 year conforming loan.
I'm in escrow with less than 4% today w no points. Took some negotiating
How to negotiate rates? What do you usually tell them in the phone ?
Shop around. Ask about relationship deals for assets under management. Ask about getting closing costs credited towards points. Tell them if you have a better offer and ask if there's any discounts the underwriter can offer