Increase in authorised/paid up capital and its effect?

Hi,

I need to give 26% of share holding to a new person joining our company. The existing paid up capital is 1,00,000/-

If we increase the paid up capital to say 2,00,000/- what happens to the existing share holders. does their share holding drop?

Also, if I want the share holding for everyone to drop so that we can give the said 26% to the new person can we do that?

And if we want selective individuals to reduce their holding and selective individuals ot increase, how do we do?