Can I withdraw H1 extension after you receieve RFE and apply for extension again once I 140 is approved?

I had applied for H1 B extension to recapture my vacation days of 3 months. Now I have received RFE asking for additional documents. Considering only 3 months to complete 6 years of H1B tenure, I am afraid that extension might get rejected. As my PERM is in progress and I 140 will be approved in few months, I was planning to leave USA a month earlier to keep my H1B status open. If my extension is rejected, I can not apply for extension once I 140 is approved.

Question is: Can I withdraw my H1B extension now after I receiving RFE and leave the country? Will that make my H1B status invalid or I can apply for extension again once I 140 is approved?

Thanks