I think you can, as long as your sister has registered you as her brother in the system, and you have done the same while applying for the PR. Just send a web form (https://secure.cic.gc.ca/enquiries-renseignements/canada-case-cas-eng.aspx?_ga-renseignements/canada-case-cas-eng.aspx?) with all the details about your case and your sisters details for confirmation that you can travel. A print of their confirmation should suffice.1. reside outside the US.
2. My sister is a citizen
3. My COPR is issued after 18 March 2020.
4. Engineer
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Can I travel guys?
Also call them up from text now app on the number 1-888-242-2100. Check here for further details for contact (https://www.canada.ca/en/immigration-refugees-citizenship/corporate/contact-ircc/client-support-centre.html).
Good luck Sam, hopefully everything goes smooth sailing.