H1 amendment withdraw and H1 Extension + Amendment

I have two cases running with USCIS, same employer.

  1. H1 Amendment

  2. H1 Extension + Amendment

  3. My H1 Amendment was filled in Apr,2018 (Client A) for which I have received RFE on Mar,2019. Currently I am not with this client. What is the best option to respond to this RFE?
    Since, I am not with this client, can we withdraw this Amendment?

  4. My i94 expires in Mar,2019 and I have already filled H1 extension (Client A) in Dec 2018.
    Now, for this case also, the client is changed.
    What should be my next action ? Need to file amendment on my existing Extension ?

Please suggest

Yes, withdraw it.

Since the extension in pending state, I guess your lawyer can write to USCIS with the pending case number to update the Client/location updates. If they didnt accept(usually they will), file amendment IMMEDIATELY after extension approval.