// This Code was made by Chinese_zjc_.
#include <bits/stdc++.h>
// #define debug
int T, n, m, a[105][105];
std::queue<std::pair<int, int>> que;
void add(int x, int y, int v)
{
    a[x][y] = v;
    for (int i = 0; i != 2; ++i)
        for (int j = 0; j != 2; ++j)
            que.push({x - i, y - j});
}
void work()
{
    while (!que.empty())
    {
        std::pair<int, int> now = que.front();
        que.pop();
        if (now.first < 0 || now.second < 0 || now.first >= n - 1 || now.second >= m - 1)
            continue;
        int cnt[3] = {0, 0, 0};
        for (int i = 0; i != 2; ++i)
            for (int j = 0; j != 2; ++j)
                ++cnt[a[now.first + i][now.second + j]];
        // std::cout << now.first << ' ' << now.second << std::endl;
        // for (int i = 0; i <= 2; ++i)
        //     std::cout << cnt[i] << " \n"[i == 2];
        if ((cnt[0] == 3 || cnt[1] == 3) && cnt[2])
            for (int i = 0; i != 2; ++i)
                for (int j = 0; j != 2; ++j)
                    if (a[now.first + i][now.second + j] == 2)
                        add(now.first + i, now.second + j, cnt[0] == 3);
    }
}
signed main()
{
    std::ios::sync_with_stdio(false);
    std::cin >> T;
    while (T--)
    {
        std::cin >> n >> m;
        for (int i = 0; i != n; ++i)
            for (int j = 0; j != m; ++j)
            {
                static char c;
                std::cin >> c;
                if (c == '?')
                    a[i][j] = 2;
                else
                    a[i][j] = (c == 'W') ^ ((i + j) & 1);
            }
        for (int i = 0; i + 1 != n; ++i)
            for (int j = 0; j + 1 != m; ++j)
                que.push({i, j});
        for (int pos = 0; pos != n * m; ++pos)
        {
            work();
            if (a[pos / m][pos % m] == 2)
                add(pos / m, pos % m, false);
        }
        bool flag = true;
        for (int i = 0; i + 1 != n; ++i)
            for (int j = 0; j + 1 != m; ++j)
                if (a[i][j] == a[i][j + 1] && a[i][j] == a[i + 1][j] && a[i][j] == a[i + 1][j + 1])
                    flag = false;
        if (flag)
        {
            std::cout << "YES" << std::endl;
            for (int i = 0; i != n; ++i, std::cout << std::endl)
                for (int j = 0; j != m; ++j)
                    std::cout << (a[i][j] ^ ((i + j) & 1) ? 'W' : 'B');
        }
        else
            std::cout << "NO" << std::endl;
    }
    return 0;
}