When you are a US person or are subject to US sanctions, if you have blocked and reported property due to mistaken identity or typographical or similar errors, you may unblock such property and file an unblocking report with OFAC consistent with the procedures described in 31 CFR 501.603(b)(3).
With respect to the information described in 31 CFR 501.603(b)(3)(ii)(F), the reporting person can cite FAQ 1196 in their unblocking report to indicate that the property was released due to mistaken identity or typographical errors, rather than an OFAC authorization like a general or specific license. Alternatively, you may seek to have such property unblocked pursuant to the administrative procedures detailed at 31 CFR 501.806, known as a "Compliance Release."
Please note, unblocking property in which a blocked person does in fact have an interest without authorization from OFAC could expose U.S. persons to civil penalties.
When you are not a US person and not subject to US sanctions, you have no legal obligation to block property under US sanctions. You should then consider to reject transactions that would be blocked by a US person after informing an involved US person of your action and why you take it (so the US person can block and report). When you only reject, you may be involved in a double potential violation.