L1b to H1B when 1 h1b is approved and 1 in rfe

From l1b to h1b change of status. If two employers have filed for h1b say e1 and e2. If e2 got case approved and e1 got rfe. Now if employee joined e2 in this scenario asnhe cant be on l1b statis, can employee join back e1 directly when they file for rfe and if their case gets approved or they need to file for tranfer.