Raise it immediately and in writing. A board's processing time is outside everyone's control, and a start date built on optimism damages the employer relationship as well as the plan.
Renegotiate the date, do not hope
When licensure controls the schedule, the honest move is to tell the employer what the board has said and to propose a start date that matches it. Employers who hire regularly across the border usually understand this better than the candidate expects, and a documented conversation about a realistic date is far less damaging than a missed one. In the meantime, work on the items that are within reach: locating citizenship evidence, obtaining institutional records that can take weeks, and confirming the details the support letter will need.
If the employer cannot hold the position, that is important information about whether the opportunity was ever compatible with the process it requires. Hypothetical example: a computer systems analyst is offered a project role with a start date tied to a software launch. The first review should result in a dependency list: citizenship document, credential evidence, employer letter, and any professional authorization, each with its issuing body and lead time.
The licensing authority or educational institution settles the slowest item, not the project manager’s target date. Begin requests for third-party records first, while the employer finalizes the duties description. A common failure is reserving travel or resigning when only the employer’s letter is ready.
The request is only as timely as its missing record, and a realistic schedule should include time for a corrected letter if the listed profession or worksite description changes.