Job change when H1B amendment is pending with USCIS?

The new employer can file its H1B petition requesting extension of status. I do not recommend working for the new employer until its H1B petition is approved granting extension of status. H1B portability rules which allow for employment by the new employer upon its filing of an H1B petition (rather than wait for approval) require that that the beneficiary be currently not violating H1B status, and more facts are needed to determine if there is a technical violation of your status until the H1B amendment is approved. Discuss further with your current immigration attorney.

You cannot work an employer other than the one who applied for you.