H1B Amendment issue

My H1 amendment got RFE because my employer failed to prove Employer employee relationship. I work for a consulting firm A, have vendor B who is associated with Client C. Since Client C don’t have policy of providing end-client letter, I was unable to provide relationship between Vendor B and Client C that caused RFE of my H1 amendment. But I have provided affidivate of two employee of client C during RFE stage. Now my amendment could get denied as my consulting firm says there are less chances that my amendment will approve. My questions are, what are the possible ways for me to stay legal in US and keep my h1 status active ? Can I transfer my H1B to some other company? How does it have any impact on my H1B? What option do I have if it gets deined? Can I work with same employer on different project at different state? If denied how much time can i stay in USA? Will I require all documents related to RFE, if transfer to some other company is possible? What can I do if transfer is possible; but I don’t have RFE response and query documents with me? If I go back to my country, after amendment is denied can some other transfer my H1B? Will their be any problem when I go for stamping?

Better option is to find another project where documents can be provided, or move to another employer.

If denied, you start accumulating out-of-status. You need to take action outlined above immediately or leave US. There is no grace period. If there is a gap, USCIS can question the same.