[URGENT] H1 petition amendment during Review

[sacca]

I already have approved unstamped H1 petition with employer A.
Employer B has submitted a 'change of employer' petition for me. This petition was NOT submitted with Premium Processing, and is currently under Initial Review.

Questions:

1. Can this second petition be amended at this stage to say 'concurrent employment'? Or can it be amended only after approval?
2. If yes to the first question, is there an amendment fee? I understand that there are USCIS amendment fees for approved petitions.

[sacca]

I already have approved unstamped H1 petition with employer A.
Employer B has submitted a 'change of employer' petition for me. This petition was NOT submitted with Premium Processing, and is currently under Initial Review.

Questions:

1. Can this second petition be amended at this stage to say 'concurrent employment'? Or can it be amended only after approval?
2. If yes to the first question, is there an amendment fee? I understand that there are USCIS amendment fees for approved petitions.

Can someone please respond?