I am a teacher. I secured a job outside of Thailand as I did my Visa

I have a Non-immigrant B visa obtained outside of Thailand.

When I came to Thailand suffice to say the job did not work out.

Can I use this same Visa (no work permit yet) for getting a new job with a new employer.

Can the first potential employer cancel the visa?

Thank you

Only an extension of stay from immigration would become invalid, so you can just stay in Thailand and look for a new employer and apply for a work permit.

Your old employer cannot cancel your stay.