L1B extension in process with RFE, H1b approved with Consular processing

[DBUS]

Hello All,

I have a complicated situation and need expert advise.

I had my L1b expired end of  June 2017 and my company applied for my extension petition (L1b individual) at the same time. Currently I am in 240 days period while decision is awaited. 

I have my H1b just approved with consular processing (somehow my company didn't opted for COS).  Now we received RFE on my L1b extension which needs to responded by Oct end, is it possible to apply for H1b COS amendment and get a decision by end of October and then withdraw the L1b due to high chances of rejection.

Need to know a solution to allow change of status on H1b without going out of the country.

As always thank you very much!