Only if that Knight had a strong position in society (ie he was a Baron, Earl, Duke, Prince, King, Pope, Doge, President), He is a Sovreign of a Order or has permmision of the Sovreign to knight a...
A knight was a noble boy who went into knight training at 7 or 8 years old and became a page. At 13-14 years old he became a squire and finally at 21 he became a full knight.