If you are no longer a partner in a partnership as of the end of any taxable year, you should not receive any more K-1 from that partnership for any subsequent taxable year. So, in your example, generally there should be nothing in your 2019 return relating to that partnership.
If you withdrew as a partner mid-way through any year, you will still receive a K-1 from that partnership for that year, but the items reported on that K-1 will be prorated (there are a couple of methods which the partnership's tax accountants may use for that) for the portion of the year during which you were a partner.
As an aside, the government doesn't "know" if you are partner or not. It's source of information for any given year is the annual partnership tax returns filed by that partnership.