I am currently on H4 EAD and also got my H1 approved this year. So, if I transfer to H1 now and may be an year later back to H4. Will my EAD be considered valid, it expires in Sept 2019. Or does the change in H4 petition invalidates the Existing EAD?
Well, I think it is best to speak to an attorney or ask USCIS to be clear. Logically, your EAD will become invalid because you changed your status and I am not sure, if they would keep your old status of H4 and the EAD details on file. So, you may have to apply again for H4 EAD. As I said, please check with USCIS, you can schedule a infopass appointment or call them.