<form method="POST" action="{{ route('Agent.ChangePass') }}">
<input type="hidden" value="{{ csrf_token() }}">
    <div class="col-sm-12 col-md-12">
        <div class="col-sm-12 col-md-12">
            <div class="form-group form-group-sm">
                <label>Old Password: </label>
                    <input type="password" class="form-control" name="old_pass" required>
            </div>
        </div>
        <div class="col-sm-12 col-md-12">
            <div class="form-group form-group-sm">
                <label>New Password: </label>
                <input type="password" class="form-control" name="new_pass" required>
            </div>
        </div>
        <div class="col-sm-12 col-md-12">
            <div class="form-group form-group-sm">
                <label>Re-enter New Password: </label>
                <input type="password" class="form-control" name="confirm_pass" required>
            </div>
                <input type="submit" class="btn btn-info btn-sm" value="Save"/>

        </div>
</div>
</form>

Route::post('Agent/ChangePass', 'AgentsController@changePass')->name('Agent.ChangePass');

public function changePass(Request $request){
    dd($request);
    if (!(Hash::check($request->get('old_pass'), Auth::user()->password))) {
        // The passwords matches
        return redirect()->back()->with("error","Your current password does not matches with the password you provided. Please try again.");
    }

    if(strcmp($request->get('confirm_pass'), $request->get('new_pass')) != 0){
        //Current password and new password are same
        return redirect()->back()->with("error","Your new password does not match your re-entered password.");
    }

    //Change Password
    $user = Auth::user()->id;
    $users = Agent::find($users);
    $users->password = bcrypt($request->get('new_pass'));
    $users->save();

    return redirect()->back()->with("success","Password changed successfully !");
}

Route::post('Agent/ChangePass', ['uses' => 'AgentsController@changePass'])->name('Agent.ChangePass');

action="{{ url('Agent/ChangePass') }}"