H1b visa interview

Hello. I got an interview appointment for my H1b. My H1 b petition is not active due to change of COS is not approved , when I file my H1 b petition was submitted “Client letter was “A “ . But now currently working on different client “B” vendor is same they find me different project . Can I use the client letter “B” for visa stamping ? Shall I do amendment?

I really appreciate if you help this matter.

Thanks
Sam

H1B amendment may be required if the job location, position and salary is different than the one with client A. Work with your employer’s immigration attorney to figure out if the amendment is required.