a 4 prong dryer plug is an apartment plug. It is designed for safety in circuit grounding. It has 4 positions.
2 hot leggs 120 volts each , a neutral line to the floating bus bar and a ground.
There was a reason for this installation.
Normally done to comply with building and electrical safety codes. Replace your dryer cord to a 4 prong plug. Carefully follow the directions supplied with the plug normally written on an instruction Faq sheet or on the inside surface of the cardboard box. Please turn off all power to the dryer circuit before attempting any electrical repairs.