#include <iostream>
#include <queue>
#include <cassert>

using namespace std;

const int N = 105;

int n, m; 
char a[N][N];
queue<pair<pair<int, int>, char>> q;

int Count (int x, int y) {
  if (!x || !y || x >= n || y >= m) return 0; 
  return ((a[x][y] == 'B') + (a[x][y + 1] == 'W') + (a[x + 1][y] == 'W') + (a[x + 1][y + 1] == 'B')) % 3 == 0 &&
         (a[x][y] == '?') + (a[x][y + 1] == '?') + (a[x + 1][y] == '?') + (a[x + 1][y + 1] == '?') == 1; 
}

void Add_limit (int x, int y) {
  char ch = ((a[x][y] == 'B') + (a[x][y + 1] == 'B') + (a[x + 1][y] == 'B') + (a[x + 1][y + 1] == 'B') == 2 ? 'B' : 'W');
  for (int ax = x; ax <= x + 1; ++ax) {
    for (int ay = y; ay <= y + 1; ++ay) {
      if (a[ax][ay] == '?') {
        q.push({{ax, ay}, ch});
      }
    }
  }
}

int main () {
  cin.tie(0)->sync_with_stdio(0);
  int T;
  cin >> T;
  while (T--) {
    [&]() -> void {
      cin >> n >> m; 
      for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
          cin >> a[i][j];
        }
      }
      for (int i = 1; i < n; ++i) {
        for (int j = 1; j < m; ++j) {
          if (Count(i, j)) {
            Add_limit(i, j);
          }
        }
      }
      for (int t = 1; t <= n * m; ) {
        if (q.empty()) {
          while (t <= n * m) {
            int x = (t - 1) / m + 1, y = (t - 1) % m + 1;
            if (a[x][y] == '?') {
              char ret = '?';
              for (int o = 0; o < 2; ++o) {
                char ch = !o ? 'W' : 'B';
                a[x][y] = ch;
                if (Count(x - 1, y - 1) + Count(x - 1, y) + Count(x, y - 1) + Count(x, y) <= 1) {
                  ret = ch;
                }
              }
              assert(ret != '?');
              q.push({{x, y}, ret});
              ++t;
              break;
            }
            ++t;
          }
          if (q.empty()) break;
        }
        pair<pair<int, int>, char> tp = q.front();
        q.pop();
        int x = tp.first.first, y = tp.first.second;
        char c = tp.second;
        a[x][y] = c;
        if (Count(x - 1, y - 1)) Add_limit(x - 1, y - 1);
        if (Count(x - 1, y)) Add_limit(x - 1, y);
        if (Count(x, y - 1)) Add_limit(x, y - 1);
        if (Count(x, y)) Add_limit(x, y);
      }
      for (int i = 1; i < n; ++i) {
        for (int j = 1; j < m; ++j) {
          if (a[i][j] == 'B' && a[i][j + 1] == 'W' && a[i + 1][j] == 'W' && a[i + 1][j + 1] == 'B' || 
              a[i][j] == 'W' && a[i][j + 1] == 'B' && a[i + 1][j] == 'B' && a[i + 1][j + 1] == 'W') {
            cout << "NO" << '\n';
            return;
          } 
        }
      }
      cout << "YES" << '\n';
      for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
          cout << a[i][j];
        }
        cout << '\n';
      }
    }();
  }
  return 0; 
}