Under the IBOR Fallbacks Protocol, the adherence procedure is complete once a party submits an adherence letter through the ISDA website and ISDA approves it. Adherence is made party by party, and it cannot be made trade by trade. Because the covered contracts between adhering parties are amended all at once, the parties do not need to sign a separate amendment contract with each counterparty.
Consider a hypothetical example in which Company X and Bank Q both adhere to the same protocol. The ISDA Master Agreement between them is amended to the terms the protocol sets out. The contract between Company X and Company R, which has not adhered to the protocol, is not amended.
A protocol is a separate document from the standard forms such as the ISDA Master Agreement. The ISDA Protocols article walks through the procedure using the IBOR Fallbacks Protocol as an example.