I want to say "I'll reply to your email tomorrow", can I use "I'll revert to you tomorrow", or "I'll revert to your email tomorrow"?
I believe that revert is used in this way in South Asian English, but not in most other variants.
This question has been asked a few times by South Asian speakers- it doesn't work for me, but it may work within that variant. Substitution is not solely dependent on whether a standard form exists- AmE spelling, for instance, was largely the work of Noah Webster and went against the grain of standard usage, so was he wrong to do that?
If the original poster is going to communicate outside of South Asia, he will need to recognize that "revert" will be seen as an error. That was my point.