"Revocate" means to call back, recall. For example, to send a message to troops to retreat. I have an excellent vocabulary, but was previously unaware this word existed, so I think it's reasonable to assume its use will usually raise eyebrows among even very fluent, well-educated speakers — most of whom will assume you misspelled "revoke". Some dictionaries mark it as obsolete, and I'm not surprised.

"Revoke", on the other hand, is a fairly common word, meaning to undo a previously-valid decision or law. For example, to cancel a previously-granted permission to do something.

If you want to use revocate, you should seriously consider simply saying "call back" or something similar instead. Even in formal uses, this will likely be the best choice; borrowing from the previous example, a military text that mentioned a general "recalling" his troops would be perfectly natural, while one that mentioned that general "revocating" his troops would be hard to understand.

"Revocation", itself, has nothing to do with "revocate", other than by etymology. It's the noun form of "revoke". So one might refer to "the revocation of an order", meaning its cancellation.

They mean the same, can be used in same place. Revocation is more eloquent

Revocation refers to the cancelling or annulment of something by some authority. When revocation happens, a privilege, title, or status is removed from someone

Revocation is not used as much. In the 80s and early 90s it was used, but i have not heard it being used for some time. It is what you would call a more eloquent form. When i did hear it used it was for titles

Example: the revocation of land titles or no revocation of title to land shall be effected This is a Petition for revocation of a Heirship Certificate a Revocation of Power of Attorney

Revoke-put an end to the validity or operation of (a decree, decision, or promise). While revoke used to be used example: your license was revoked. your privilege was revoked

I have been an attorney in southwest Wisconsin for the past ~14 years and revocate is a word which only comes up in my life in the context of probation/extended supervision/parole revocation proceedings. It is a word used earnestly by probationers instead of revoke or revocation in a context like "My P.O. (probation officer) wants to revocate me." Since probationers facing revocation proceedings are always or almost always held in a county jail while the revocation proceedings are pending in my area, and because prisoners in my experience are prone to try to fit in with other cellmates as a way of not showing weakness (thereby exposing themselves to increased risks of physical attacks or other exploitation), it seems possible that the use of revocate has caught on partially as an affectation by people trying to sound more "street."